1 /*
2 * Copyright (c) 1997, 2018, 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/compileLog.hpp"
33 #include "compiler/disassembler.hpp"
34 #include "compiler/oopMap.hpp"
35 #if INCLUDE_JFR
36 #include "jfr/jfrEvents.hpp"
37 #endif
38 #include "opto/addnode.hpp"
39 #include "opto/block.hpp"
40 #include "opto/c2compiler.hpp"
41 #include "opto/callGenerator.hpp"
42 #include "opto/callnode.hpp"
43 #include "opto/cfgnode.hpp"
44 #include "opto/chaitin.hpp"
45 #include "opto/compile.hpp"
46 #include "opto/connode.hpp"
47 #include "opto/divnode.hpp"
48 #include "opto/escape.hpp"
49 #include "opto/idealGraphPrinter.hpp"
50 #include "opto/loopnode.hpp"
51 #include "opto/machnode.hpp"
52 #include "opto/macro.hpp"
53 #include "opto/matcher.hpp"
54 #include "opto/mathexactnode.hpp"
55 #include "opto/memnode.hpp"
56 #include "opto/mulnode.hpp"
57 #include "opto/node.hpp"
58 #include "opto/opcodes.hpp"
59 #include "opto/output.hpp"
60 #include "opto/parse.hpp"
61 #include "opto/phaseX.hpp"
62 #include "opto/rootnode.hpp"
63 #include "opto/runtime.hpp"
64 #include "opto/stringopts.hpp"
65 #include "opto/type.hpp"
66 #include "opto/vectornode.hpp"
67 #include "runtime/arguments.hpp"
68 #include "runtime/signature.hpp"
69 #include "runtime/stubRoutines.hpp"
70 #include "runtime/timer.hpp"
71 #include "utilities/copy.hpp"
72 #if defined AD_MD_HPP
73 # include AD_MD_HPP
74 #elif defined TARGET_ARCH_MODEL_x86_32
75 # include "adfiles/ad_x86_32.hpp"
76 #elif defined TARGET_ARCH_MODEL_x86_64
77 # include "adfiles/ad_x86_64.hpp"
78 #elif defined TARGET_ARCH_MODEL_sparc
79 # include "adfiles/ad_sparc.hpp"
80 #elif defined TARGET_ARCH_MODEL_zero
81 # include "adfiles/ad_zero.hpp"
82 #elif defined TARGET_ARCH_MODEL_ppc_64
83 # include "adfiles/ad_ppc_64.hpp"
84 #endif
85
86 // -------------------- Compile::mach_constant_base_node -----------------------
87 // Constant table base node singleton.
88 MachConstantBaseNode* Compile::mach_constant_base_node() {
89 if (_mach_constant_base_node == NULL) {
90 _mach_constant_base_node = new (C) MachConstantBaseNode();
91 _mach_constant_base_node->add_req(C->root());
92 }
93 return _mach_constant_base_node;
94 }
95
96
97 /// Support for intrinsics.
98
99 // Return the index at which m must be inserted (or already exists).
100 // The sort order is by the address of the ciMethod, with is_virtual as minor key.
101 int Compile::intrinsic_insertion_index(ciMethod* m, bool is_virtual) {
102 #ifdef ASSERT
103 for (int i = 1; i < _intrinsics->length(); i++) {
104 CallGenerator* cg1 = _intrinsics->at(i-1);
105 CallGenerator* cg2 = _intrinsics->at(i);
106 assert(cg1->method() != cg2->method()
107 ? cg1->method() < cg2->method()
108 : cg1->is_virtual() < cg2->is_virtual(),
109 "compiler intrinsics list must stay sorted");
110 }
111 #endif
112 // Binary search sorted list, in decreasing intervals [lo, hi].
113 int lo = 0, hi = _intrinsics->length()-1;
114 while (lo <= hi) {
115 int mid = (uint)(hi + lo) / 2;
116 ciMethod* mid_m = _intrinsics->at(mid)->method();
117 if (m < mid_m) {
118 hi = mid-1;
119 } else if (m > mid_m) {
120 lo = mid+1;
121 } else {
122 // look at minor sort key
123 bool mid_virt = _intrinsics->at(mid)->is_virtual();
124 if (is_virtual < mid_virt) {
125 hi = mid-1;
126 } else if (is_virtual > mid_virt) {
127 lo = mid+1;
128 } else {
129 return mid; // exact match
130 }
131 }
132 }
133 return lo; // inexact match
134 }
135
136 void Compile::register_intrinsic(CallGenerator* cg) {
137 if (_intrinsics == NULL) {
138 _intrinsics = new (comp_arena())GrowableArray<CallGenerator*>(comp_arena(), 60, 0, NULL);
139 }
140 // This code is stolen from ciObjectFactory::insert.
141 // Really, GrowableArray should have methods for
142 // insert_at, remove_at, and binary_search.
143 int len = _intrinsics->length();
144 int index = intrinsic_insertion_index(cg->method(), cg->is_virtual());
145 if (index == len) {
146 _intrinsics->append(cg);
147 } else {
148 #ifdef ASSERT
149 CallGenerator* oldcg = _intrinsics->at(index);
150 assert(oldcg->method() != cg->method() || oldcg->is_virtual() != cg->is_virtual(), "don't register twice");
151 #endif
152 _intrinsics->append(_intrinsics->at(len-1));
153 int pos;
154 for (pos = len-2; pos >= index; pos--) {
155 _intrinsics->at_put(pos+1,_intrinsics->at(pos));
156 }
157 _intrinsics->at_put(index, cg);
158 }
159 assert(find_intrinsic(cg->method(), cg->is_virtual()) == cg, "registration worked");
160 }
161
162 CallGenerator* Compile::find_intrinsic(ciMethod* m, bool is_virtual) {
163 assert(m->is_loaded(), "don't try this on unloaded methods");
164 if (_intrinsics != NULL) {
165 int index = intrinsic_insertion_index(m, is_virtual);
166 if (index < _intrinsics->length()
167 && _intrinsics->at(index)->method() == m
168 && _intrinsics->at(index)->is_virtual() == is_virtual) {
169 return _intrinsics->at(index);
170 }
171 }
172 // Lazily create intrinsics for intrinsic IDs well-known in the runtime.
173 if (m->intrinsic_id() != vmIntrinsics::_none &&
174 m->intrinsic_id() <= vmIntrinsics::LAST_COMPILER_INLINE) {
175 CallGenerator* cg = make_vm_intrinsic(m, is_virtual);
176 if (cg != NULL) {
177 // Save it for next time:
178 register_intrinsic(cg);
179 return cg;
180 } else {
181 gather_intrinsic_statistics(m->intrinsic_id(), is_virtual, _intrinsic_disabled);
182 }
183 }
184 return NULL;
185 }
186
187 // Compile:: register_library_intrinsics and make_vm_intrinsic are defined
188 // in library_call.cpp.
189
190
191 #ifndef PRODUCT
192 // statistics gathering...
193
194 juint Compile::_intrinsic_hist_count[vmIntrinsics::ID_LIMIT] = {0};
195 jubyte Compile::_intrinsic_hist_flags[vmIntrinsics::ID_LIMIT] = {0};
196
197 bool Compile::gather_intrinsic_statistics(vmIntrinsics::ID id, bool is_virtual, int flags) {
198 assert(id > vmIntrinsics::_none && id < vmIntrinsics::ID_LIMIT, "oob");
199 int oflags = _intrinsic_hist_flags[id];
200 assert(flags != 0, "what happened?");
201 if (is_virtual) {
202 flags |= _intrinsic_virtual;
203 }
204 bool changed = (flags != oflags);
205 if ((flags & _intrinsic_worked) != 0) {
206 juint count = (_intrinsic_hist_count[id] += 1);
207 if (count == 1) {
208 changed = true; // first time
209 }
210 // increment the overall count also:
211 _intrinsic_hist_count[vmIntrinsics::_none] += 1;
212 }
213 if (changed) {
214 if (((oflags ^ flags) & _intrinsic_virtual) != 0) {
215 // Something changed about the intrinsic's virtuality.
216 if ((flags & _intrinsic_virtual) != 0) {
217 // This is the first use of this intrinsic as a virtual call.
218 if (oflags != 0) {
219 // We already saw it as a non-virtual, so note both cases.
220 flags |= _intrinsic_both;
221 }
222 } else if ((oflags & _intrinsic_both) == 0) {
223 // This is the first use of this intrinsic as a non-virtual
224 flags |= _intrinsic_both;
225 }
226 }
227 _intrinsic_hist_flags[id] = (jubyte) (oflags | flags);
228 }
229 // update the overall flags also:
230 _intrinsic_hist_flags[vmIntrinsics::_none] |= (jubyte) flags;
231 return changed;
232 }
233
234 static char* format_flags(int flags, char* buf) {
235 buf[0] = 0;
236 if ((flags & Compile::_intrinsic_worked) != 0) strcat(buf, ",worked");
237 if ((flags & Compile::_intrinsic_failed) != 0) strcat(buf, ",failed");
238 if ((flags & Compile::_intrinsic_disabled) != 0) strcat(buf, ",disabled");
239 if ((flags & Compile::_intrinsic_virtual) != 0) strcat(buf, ",virtual");
240 if ((flags & Compile::_intrinsic_both) != 0) strcat(buf, ",nonvirtual");
241 if (buf[0] == 0) strcat(buf, ",");
242 assert(buf[0] == ',', "must be");
243 return &buf[1];
244 }
245
246 void Compile::print_intrinsic_statistics() {
247 char flagsbuf[100];
248 ttyLocker ttyl;
249 if (xtty != NULL) xtty->head("statistics type='intrinsic'");
250 tty->print_cr("Compiler intrinsic usage:");
251 juint total = _intrinsic_hist_count[vmIntrinsics::_none];
252 if (total == 0) total = 1; // avoid div0 in case of no successes
253 #define PRINT_STAT_LINE(name, c, f) \
254 tty->print_cr(" %4d (%4.1f%%) %s (%s)", (int)(c), ((c) * 100.0) / total, name, f);
255 for (int index = 1 + (int)vmIntrinsics::_none; index < (int)vmIntrinsics::ID_LIMIT; index++) {
256 vmIntrinsics::ID id = (vmIntrinsics::ID) index;
257 int flags = _intrinsic_hist_flags[id];
258 juint count = _intrinsic_hist_count[id];
259 if ((flags | count) != 0) {
260 PRINT_STAT_LINE(vmIntrinsics::name_at(id), count, format_flags(flags, flagsbuf));
261 }
262 }
263 PRINT_STAT_LINE("total", total, format_flags(_intrinsic_hist_flags[vmIntrinsics::_none], flagsbuf));
264 if (xtty != NULL) xtty->tail("statistics");
265 }
266
267 void Compile::print_statistics() {
268 { ttyLocker ttyl;
269 if (xtty != NULL) xtty->head("statistics type='opto'");
270 Parse::print_statistics();
271 PhaseCCP::print_statistics();
272 PhaseRegAlloc::print_statistics();
273 Scheduling::print_statistics();
274 PhasePeephole::print_statistics();
275 PhaseIdealLoop::print_statistics();
276 if (xtty != NULL) xtty->tail("statistics");
277 }
278 if (_intrinsic_hist_flags[vmIntrinsics::_none] != 0) {
279 // put this under its own <statistics> element.
280 print_intrinsic_statistics();
281 }
282 }
283 #endif //PRODUCT
284
285 // Support for bundling info
286 Bundle* Compile::node_bundling(const Node *n) {
287 assert(valid_bundle_info(n), "oob");
288 return &_node_bundling_base[n->_idx];
289 }
290
291 bool Compile::valid_bundle_info(const Node *n) {
292 return (_node_bundling_limit > n->_idx);
293 }
294
295
296 void Compile::gvn_replace_by(Node* n, Node* nn) {
297 for (DUIterator_Last imin, i = n->last_outs(imin); i >= imin; ) {
298 Node* use = n->last_out(i);
299 bool is_in_table = initial_gvn()->hash_delete(use);
300 uint uses_found = 0;
301 for (uint j = 0; j < use->len(); j++) {
302 if (use->in(j) == n) {
303 if (j < use->req())
304 use->set_req(j, nn);
305 else
306 use->set_prec(j, nn);
307 uses_found++;
308 }
309 }
310 if (is_in_table) {
311 // reinsert into table
312 initial_gvn()->hash_find_insert(use);
313 }
314 record_for_igvn(use);
315 i -= uses_found; // we deleted 1 or more copies of this edge
316 }
317 }
318
319
320 static inline bool not_a_node(const Node* n) {
321 if (n == NULL) return true;
322 if (((intptr_t)n & 1) != 0) return true; // uninitialized, etc.
323 if (*(address*)n == badAddress) return true; // kill by Node::destruct
324 return false;
325 }
326
327 // Identify all nodes that are reachable from below, useful.
328 // Use breadth-first pass that records state in a Unique_Node_List,
329 // recursive traversal is slower.
330 void Compile::identify_useful_nodes(Unique_Node_List &useful) {
331 int estimated_worklist_size = live_nodes();
332 useful.map( estimated_worklist_size, NULL ); // preallocate space
333
334 // Initialize worklist
335 if (root() != NULL) { useful.push(root()); }
336 // If 'top' is cached, declare it useful to preserve cached node
337 if( cached_top_node() ) { useful.push(cached_top_node()); }
338
339 // Push all useful nodes onto the list, breadthfirst
340 for( uint next = 0; next < useful.size(); ++next ) {
341 assert( next < unique(), "Unique useful nodes < total nodes");
342 Node *n = useful.at(next);
343 uint max = n->len();
344 for( uint i = 0; i < max; ++i ) {
345 Node *m = n->in(i);
346 if (not_a_node(m)) continue;
347 useful.push(m);
348 }
349 }
350 }
351
352 // Update dead_node_list with any missing dead nodes using useful
353 // list. Consider all non-useful nodes to be useless i.e., dead nodes.
354 void Compile::update_dead_node_list(Unique_Node_List &useful) {
355 uint max_idx = unique();
356 VectorSet& useful_node_set = useful.member_set();
357
358 for (uint node_idx = 0; node_idx < max_idx; node_idx++) {
359 // If node with index node_idx is not in useful set,
360 // mark it as dead in dead node list.
361 if (! useful_node_set.test(node_idx) ) {
362 record_dead_node(node_idx);
363 }
364 }
365 }
366
367 void Compile::remove_useless_late_inlines(GrowableArray<CallGenerator*>* inlines, Unique_Node_List &useful) {
368 int shift = 0;
369 for (int i = 0; i < inlines->length(); i++) {
370 CallGenerator* cg = inlines->at(i);
371 CallNode* call = cg->call_node();
372 if (shift > 0) {
373 inlines->at_put(i-shift, cg);
374 }
375 if (!useful.member(call)) {
376 shift++;
377 }
378 }
379 inlines->trunc_to(inlines->length()-shift);
380 }
381
382 // Disconnect all useless nodes by disconnecting those at the boundary.
383 void Compile::remove_useless_nodes(Unique_Node_List &useful) {
384 uint next = 0;
385 while (next < useful.size()) {
386 Node *n = useful.at(next++);
387 if (n->is_SafePoint()) {
388 // We're done with a parsing phase. Replaced nodes are not valid
389 // beyond that point.
390 n->as_SafePoint()->delete_replaced_nodes();
391 }
392 // Use raw traversal of out edges since this code removes out edges
393 int max = n->outcnt();
394 for (int j = 0; j < max; ++j) {
395 Node* child = n->raw_out(j);
396 if (! useful.member(child)) {
397 assert(!child->is_top() || child != top(),
398 "If top is cached in Compile object it is in useful list");
399 // Only need to remove this out-edge to the useless node
400 n->raw_del_out(j);
401 --j;
402 --max;
403 }
404 }
405 if (n->outcnt() == 1 && n->has_special_unique_user()) {
406 record_for_igvn(n->unique_out());
407 }
408 }
409 // Remove useless macro and predicate opaq nodes
410 for (int i = C->macro_count()-1; i >= 0; i--) {
411 Node* n = C->macro_node(i);
412 if (!useful.member(n)) {
413 remove_macro_node(n);
414 }
415 }
416 // Remove useless CastII nodes with range check dependency
417 for (int i = range_check_cast_count() - 1; i >= 0; i--) {
418 Node* cast = range_check_cast_node(i);
419 if (!useful.member(cast)) {
420 remove_range_check_cast(cast);
421 }
422 }
423 // Remove useless expensive node
424 for (int i = C->expensive_count()-1; i >= 0; i--) {
425 Node* n = C->expensive_node(i);
426 if (!useful.member(n)) {
427 remove_expensive_node(n);
428 }
429 }
430 // clean up the late inline lists
431 remove_useless_late_inlines(&_string_late_inlines, useful);
432 remove_useless_late_inlines(&_boxing_late_inlines, useful);
433 remove_useless_late_inlines(&_late_inlines, useful);
434 debug_only(verify_graph_edges(true/*check for no_dead_code*/);)
435 }
436
437 //------------------------------frame_size_in_words-----------------------------
438 // frame_slots in units of words
439 int Compile::frame_size_in_words() const {
440 // shift is 0 in LP32 and 1 in LP64
441 const int shift = (LogBytesPerWord - LogBytesPerInt);
442 int words = _frame_slots >> shift;
443 assert( words << shift == _frame_slots, "frame size must be properly aligned in LP64" );
444 return words;
445 }
446
447 // To bang the stack of this compiled method we use the stack size
448 // that the interpreter would need in case of a deoptimization. This
449 // removes the need to bang the stack in the deoptimization blob which
450 // in turn simplifies stack overflow handling.
451 int Compile::bang_size_in_bytes() const {
452 return MAX2(_interpreter_frame_size, frame_size_in_bytes());
453 }
454
455 // ============================================================================
456 //------------------------------CompileWrapper---------------------------------
457 class CompileWrapper : public StackObj {
458 Compile *const _compile;
459 public:
460 CompileWrapper(Compile* compile);
461
462 ~CompileWrapper();
463 };
464
465 CompileWrapper::CompileWrapper(Compile* compile) : _compile(compile) {
466 // the Compile* pointer is stored in the current ciEnv:
467 ciEnv* env = compile->env();
468 assert(env == ciEnv::current(), "must already be a ciEnv active");
469 assert(env->compiler_data() == NULL, "compile already active?");
470 env->set_compiler_data(compile);
471 assert(compile == Compile::current(), "sanity");
472
473 compile->set_type_dict(NULL);
474 compile->set_type_hwm(NULL);
475 compile->set_type_last_size(0);
476 compile->set_last_tf(NULL, NULL);
477 compile->set_indexSet_arena(NULL);
478 compile->set_indexSet_free_block_list(NULL);
479 compile->init_type_arena();
480 Type::Initialize(compile);
481 _compile->set_scratch_buffer_blob(NULL);
482 _compile->begin_method();
483 }
484 CompileWrapper::~CompileWrapper() {
485 _compile->end_method();
486 if (_compile->scratch_buffer_blob() != NULL)
487 BufferBlob::free(_compile->scratch_buffer_blob());
488 _compile->env()->set_compiler_data(NULL);
489 }
490
491
492 //----------------------------print_compile_messages---------------------------
493 void Compile::print_compile_messages() {
494 #ifndef PRODUCT
495 // Check if recompiling
496 if (_subsume_loads == false && PrintOpto) {
497 // Recompiling without allowing machine instructions to subsume loads
498 tty->print_cr("*********************************************************");
499 tty->print_cr("** Bailout: Recompile without subsuming loads **");
500 tty->print_cr("*********************************************************");
501 }
502 if (_do_escape_analysis != DoEscapeAnalysis && PrintOpto) {
503 // Recompiling without escape analysis
504 tty->print_cr("*********************************************************");
505 tty->print_cr("** Bailout: Recompile without escape analysis **");
506 tty->print_cr("*********************************************************");
507 }
508 if (_eliminate_boxing != EliminateAutoBox && PrintOpto) {
509 // Recompiling without boxing elimination
510 tty->print_cr("*********************************************************");
511 tty->print_cr("** Bailout: Recompile without boxing elimination **");
512 tty->print_cr("*********************************************************");
513 }
514 if (env()->break_at_compile()) {
515 // Open the debugger when compiling this method.
516 tty->print("### Breaking when compiling: ");
517 method()->print_short_name();
518 tty->cr();
519 BREAKPOINT;
520 }
521
522 if( PrintOpto ) {
523 if (is_osr_compilation()) {
524 tty->print("[OSR]%3d", _compile_id);
525 } else {
526 tty->print("%3d", _compile_id);
527 }
528 }
529 #endif
530 }
531
532
533 //-----------------------init_scratch_buffer_blob------------------------------
534 // Construct a temporary BufferBlob and cache it for this compile.
535 void Compile::init_scratch_buffer_blob(int const_size) {
536 // If there is already a scratch buffer blob allocated and the
537 // constant section is big enough, use it. Otherwise free the
538 // current and allocate a new one.
539 BufferBlob* blob = scratch_buffer_blob();
540 if ((blob != NULL) && (const_size <= _scratch_const_size)) {
541 // Use the current blob.
542 } else {
543 if (blob != NULL) {
544 BufferBlob::free(blob);
545 }
546
547 ResourceMark rm;
548 _scratch_const_size = const_size;
549 int size = (MAX_inst_size + MAX_stubs_size + _scratch_const_size);
550 blob = BufferBlob::create("Compile::scratch_buffer", size);
551 // Record the buffer blob for next time.
552 set_scratch_buffer_blob(blob);
553 // Have we run out of code space?
554 if (scratch_buffer_blob() == NULL) {
555 // Let CompilerBroker disable further compilations.
556 record_failure("Not enough space for scratch buffer in CodeCache");
557 return;
558 }
559 }
560
561 // Initialize the relocation buffers
562 relocInfo* locs_buf = (relocInfo*) blob->content_end() - MAX_locs_size;
563 set_scratch_locs_memory(locs_buf);
564 }
565
566
567 //-----------------------scratch_emit_size-------------------------------------
568 // Helper function that computes size by emitting code
569 uint Compile::scratch_emit_size(const Node* n) {
570 // Start scratch_emit_size section.
571 set_in_scratch_emit_size(true);
572
573 // Emit into a trash buffer and count bytes emitted.
574 // This is a pretty expensive way to compute a size,
575 // but it works well enough if seldom used.
576 // All common fixed-size instructions are given a size
577 // method by the AD file.
578 // Note that the scratch buffer blob and locs memory are
579 // allocated at the beginning of the compile task, and
580 // may be shared by several calls to scratch_emit_size.
581 // The allocation of the scratch buffer blob is particularly
582 // expensive, since it has to grab the code cache lock.
583 BufferBlob* blob = this->scratch_buffer_blob();
584 assert(blob != NULL, "Initialize BufferBlob at start");
585 assert(blob->size() > MAX_inst_size, "sanity");
586 relocInfo* locs_buf = scratch_locs_memory();
587 address blob_begin = blob->content_begin();
588 address blob_end = (address)locs_buf;
589 assert(blob->content_contains(blob_end), "sanity");
590 CodeBuffer buf(blob_begin, blob_end - blob_begin);
591 buf.initialize_consts_size(_scratch_const_size);
592 buf.initialize_stubs_size(MAX_stubs_size);
593 assert(locs_buf != NULL, "sanity");
594 int lsize = MAX_locs_size / 3;
595 buf.consts()->initialize_shared_locs(&locs_buf[lsize * 0], lsize);
596 buf.insts()->initialize_shared_locs( &locs_buf[lsize * 1], lsize);
597 buf.stubs()->initialize_shared_locs( &locs_buf[lsize * 2], lsize);
598
599 // Do the emission.
600
601 Label fakeL; // Fake label for branch instructions.
602 Label* saveL = NULL;
603 uint save_bnum = 0;
604 bool is_branch = n->is_MachBranch();
605 if (is_branch) {
606 MacroAssembler masm(&buf);
607 masm.bind(fakeL);
608 n->as_MachBranch()->save_label(&saveL, &save_bnum);
609 n->as_MachBranch()->label_set(&fakeL, 0);
610 }
611 n->emit(buf, this->regalloc());
612
613 // Emitting into the scratch buffer should not fail
614 assert (!failing(), err_msg_res("Must not have pending failure. Reason is: %s", failure_reason()));
615
616 if (is_branch) // Restore label.
617 n->as_MachBranch()->label_set(saveL, save_bnum);
618
619 // End scratch_emit_size section.
620 set_in_scratch_emit_size(false);
621
622 return buf.insts_size();
623 }
624
625
626 // ============================================================================
627 //------------------------------Compile standard-------------------------------
628 debug_only( int Compile::_debug_idx = 100000; )
629
630 // Compile a method. entry_bci is -1 for normal compilations and indicates
631 // the continuation bci for on stack replacement.
632
633
634 Compile::Compile( ciEnv* ci_env, C2Compiler* compiler, ciMethod* target, int osr_bci,
635 bool subsume_loads, bool do_escape_analysis, bool eliminate_boxing )
636 : Phase(Compiler),
637 _env(ci_env),
638 _log(ci_env->log()),
639 _compile_id(ci_env->compile_id()),
640 _save_argument_registers(false),
641 _stub_name(NULL),
642 _stub_function(NULL),
643 _stub_entry_point(NULL),
644 _method(target),
645 _entry_bci(osr_bci),
646 _initial_gvn(NULL),
647 _for_igvn(NULL),
648 _warm_calls(NULL),
649 _subsume_loads(subsume_loads),
650 _do_escape_analysis(do_escape_analysis),
651 _eliminate_boxing(eliminate_boxing),
652 _failure_reason(NULL),
653 _code_buffer("Compile::Fill_buffer"),
654 _orig_pc_slot(0),
655 _orig_pc_slot_offset_in_bytes(0),
656 _has_method_handle_invokes(false),
657 _mach_constant_base_node(NULL),
658 _node_bundling_limit(0),
659 _node_bundling_base(NULL),
660 _java_calls(0),
661 _inner_loops(0),
662 _scratch_const_size(-1),
663 _in_scratch_emit_size(false),
664 _dead_node_list(comp_arena()),
665 _dead_node_count(0),
666 #ifndef PRODUCT
667 _trace_opto_output(TraceOptoOutput || method()->has_option("TraceOptoOutput")),
668 _in_dump_cnt(0),
669 _printer(IdealGraphPrinter::printer()),
670 #endif
671 _congraph(NULL),
672 _comp_arena(mtCompiler),
673 _node_arena(mtCompiler),
674 _old_arena(mtCompiler),
675 _Compile_types(mtCompiler),
676 _replay_inline_data(NULL),
677 _late_inlines(comp_arena(), 2, 0, NULL),
678 _string_late_inlines(comp_arena(), 2, 0, NULL),
679 _boxing_late_inlines(comp_arena(), 2, 0, NULL),
680 _late_inlines_pos(0),
681 _number_of_mh_late_inlines(0),
682 _inlining_progress(false),
683 _inlining_incrementally(false),
684 _print_inlining_list(NULL),
685 _print_inlining_idx(0),
686 _interpreter_frame_size(0),
687 _max_node_limit(MaxNodeLimit) {
688 C = this;
689
690 CompileWrapper cw(this);
691 #ifndef PRODUCT
692 if (TimeCompiler2) {
693 tty->print(" ");
694 target->holder()->name()->print();
695 tty->print(".");
696 target->print_short_name();
697 tty->print(" ");
698 }
699 TraceTime t1("Total compilation time", &_t_totalCompilation, TimeCompiler, TimeCompiler2);
700 TraceTime t2(NULL, &_t_methodCompilation, TimeCompiler, false);
701 bool print_opto_assembly = PrintOptoAssembly || _method->has_option("PrintOptoAssembly");
702 if (!print_opto_assembly) {
703 bool print_assembly = (PrintAssembly || _method->should_print_assembly());
704 if (print_assembly && !Disassembler::can_decode()) {
705 tty->print_cr("PrintAssembly request changed to PrintOptoAssembly");
706 print_opto_assembly = true;
707 }
708 }
709 set_print_assembly(print_opto_assembly);
710 set_parsed_irreducible_loop(false);
711
712 if (method()->has_option("ReplayInline")) {
713 _replay_inline_data = ciReplay::load_inline_data(method(), entry_bci(), ci_env->comp_level());
714 }
715 #endif
716 set_print_inlining(PrintInlining || method()->has_option("PrintInlining") NOT_PRODUCT( || PrintOptoInlining));
717 set_print_intrinsics(PrintIntrinsics || method()->has_option("PrintIntrinsics"));
718 set_has_irreducible_loop(true); // conservative until build_loop_tree() reset it
719
720 if (ProfileTraps RTM_OPT_ONLY( || UseRTMLocking )) {
721 // Make sure the method being compiled gets its own MDO,
722 // so we can at least track the decompile_count().
723 // Need MDO to record RTM code generation state.
724 method()->ensure_method_data();
725 }
726
727 Init(::AliasLevel);
728
729
730 print_compile_messages();
731
732 _ilt = InlineTree::build_inline_tree_root();
733
734 // Even if NO memory addresses are used, MergeMem nodes must have at least 1 slice
735 assert(num_alias_types() >= AliasIdxRaw, "");
736
737 #define MINIMUM_NODE_HASH 1023
738 // Node list that Iterative GVN will start with
739 Unique_Node_List for_igvn(comp_arena());
740 set_for_igvn(&for_igvn);
741
742 // GVN that will be run immediately on new nodes
743 uint estimated_size = method()->code_size()*4+64;
744 estimated_size = (estimated_size < MINIMUM_NODE_HASH ? MINIMUM_NODE_HASH : estimated_size);
745 PhaseGVN gvn(node_arena(), estimated_size);
746 set_initial_gvn(&gvn);
747
748 if (print_inlining() || print_intrinsics()) {
749 _print_inlining_list = new (comp_arena())GrowableArray<PrintInliningBuffer>(comp_arena(), 1, 1, PrintInliningBuffer());
750 }
751 { // Scope for timing the parser
752 TracePhase t3("parse", &_t_parser, true);
753
754 // Put top into the hash table ASAP.
755 initial_gvn()->transform_no_reclaim(top());
756
757 // Set up tf(), start(), and find a CallGenerator.
758 CallGenerator* cg = NULL;
759 if (is_osr_compilation()) {
760 const TypeTuple *domain = StartOSRNode::osr_domain();
761 const TypeTuple *range = TypeTuple::make_range(method()->signature());
762 init_tf(TypeFunc::make(domain, range));
763 StartNode* s = new (this) StartOSRNode(root(), domain);
764 initial_gvn()->set_type_bottom(s);
765 init_start(s);
766 cg = CallGenerator::for_osr(method(), entry_bci());
767 } else {
768 // Normal case.
769 init_tf(TypeFunc::make(method()));
770 StartNode* s = new (this) StartNode(root(), tf()->domain());
771 initial_gvn()->set_type_bottom(s);
772 init_start(s);
773 if (method()->intrinsic_id() == vmIntrinsics::_Reference_get && UseG1GC) {
774 // With java.lang.ref.reference.get() we must go through the
775 // intrinsic when G1 is enabled - even when get() is the root
776 // method of the compile - so that, if necessary, the value in
777 // the referent field of the reference object gets recorded by
778 // the pre-barrier code.
779 // Specifically, if G1 is enabled, the value in the referent
780 // field is recorded by the G1 SATB pre barrier. This will
781 // result in the referent being marked live and the reference
782 // object removed from the list of discovered references during
783 // reference processing.
784 cg = find_intrinsic(method(), false);
785 }
786 if (cg == NULL) {
787 float past_uses = method()->interpreter_invocation_count();
788 float expected_uses = past_uses;
789 cg = CallGenerator::for_inline(method(), expected_uses);
790 }
791 }
792 if (failing()) return;
793 if (cg == NULL) {
794 record_method_not_compilable_all_tiers("cannot parse method");
795 return;
796 }
797 JVMState* jvms = build_start_state(start(), tf());
798 if ((jvms = cg->generate(jvms)) == NULL) {
799 if (!failure_reason_is(C2Compiler::retry_class_loading_during_parsing())) {
800 record_method_not_compilable("method parse failed");
801 }
802 return;
803 }
804 GraphKit kit(jvms);
805
806 if (!kit.stopped()) {
807 // Accept return values, and transfer control we know not where.
808 // This is done by a special, unique ReturnNode bound to root.
809 return_values(kit.jvms());
810 }
811
812 if (kit.has_exceptions()) {
813 // Any exceptions that escape from this call must be rethrown
814 // to whatever caller is dynamically above us on the stack.
815 // This is done by a special, unique RethrowNode bound to root.
816 rethrow_exceptions(kit.transfer_exceptions_into_jvms());
817 }
818
819 assert(IncrementalInline || (_late_inlines.length() == 0 && !has_mh_late_inlines()), "incremental inlining is off");
820
821 if (_late_inlines.length() == 0 && !has_mh_late_inlines() && !failing() && has_stringbuilder()) {
822 inline_string_calls(true);
823 }
824
825 if (failing()) return;
826
827 print_method(PHASE_BEFORE_REMOVEUSELESS, 3);
828
829 // Remove clutter produced by parsing.
830 if (!failing()) {
831 ResourceMark rm;
832 PhaseRemoveUseless pru(initial_gvn(), &for_igvn);
833 }
834 }
835
836 // Note: Large methods are capped off in do_one_bytecode().
837 if (failing()) return;
838
839 // After parsing, node notes are no longer automagic.
840 // They must be propagated by register_new_node_with_optimizer(),
841 // clone(), or the like.
842 set_default_node_notes(NULL);
843
844 for (;;) {
845 int successes = Inline_Warm();
846 if (failing()) return;
847 if (successes == 0) break;
848 }
849
850 // Drain the list.
851 Finish_Warm();
852 #ifndef PRODUCT
853 if (_printer) {
854 _printer->print_inlining(this);
855 }
856 #endif
857
858 if (failing()) return;
859 NOT_PRODUCT( verify_graph_edges(); )
860
861 // Now optimize
862 Optimize();
863 if (failing()) return;
864 NOT_PRODUCT( verify_graph_edges(); )
865
866 #ifndef PRODUCT
867 if (PrintIdeal) {
868 ttyLocker ttyl; // keep the following output all in one block
869 // This output goes directly to the tty, not the compiler log.
870 // To enable tools to match it up with the compilation activity,
871 // be sure to tag this tty output with the compile ID.
872 if (xtty != NULL) {
873 xtty->head("ideal compile_id='%d'%s", compile_id(),
874 is_osr_compilation() ? " compile_kind='osr'" :
875 "");
876 }
877 root()->dump(9999);
878 if (xtty != NULL) {
879 xtty->tail("ideal");
880 }
881 }
882 #endif
883
884 NOT_PRODUCT( verify_barriers(); )
885
886 // Dump compilation data to replay it.
887 if (method()->has_option("DumpReplay")) {
888 env()->dump_replay_data(_compile_id);
889 }
890 if (method()->has_option("DumpInline") && (ilt() != NULL)) {
891 env()->dump_inline_data(_compile_id);
892 }
893
894 // Now that we know the size of all the monitors we can add a fixed slot
895 // for the original deopt pc.
896
897 _orig_pc_slot = fixed_slots();
898 int next_slot = _orig_pc_slot + (sizeof(address) / VMRegImpl::stack_slot_size);
899 set_fixed_slots(next_slot);
900
901 // Compute when to use implicit null checks. Used by matching trap based
902 // nodes and NullCheck optimization.
903 set_allowed_deopt_reasons();
904
905 // Now generate code
906 Code_Gen();
907 if (failing()) return;
908
909 // Check if we want to skip execution of all compiled code.
910 {
911 #ifndef PRODUCT
912 if (OptoNoExecute) {
913 record_method_not_compilable("+OptoNoExecute"); // Flag as failed
914 return;
915 }
916 TracePhase t2("install_code", &_t_registerMethod, TimeCompiler);
917 #endif
918
919 if (is_osr_compilation()) {
920 _code_offsets.set_value(CodeOffsets::Verified_Entry, 0);
921 _code_offsets.set_value(CodeOffsets::OSR_Entry, _first_block_size);
922 } else {
923 _code_offsets.set_value(CodeOffsets::Verified_Entry, _first_block_size);
924 _code_offsets.set_value(CodeOffsets::OSR_Entry, 0);
925 }
926
927 env()->register_method(_method, _entry_bci,
928 &_code_offsets,
929 _orig_pc_slot_offset_in_bytes,
930 code_buffer(),
931 frame_size_in_words(), _oop_map_set,
932 &_handler_table, &_inc_table,
933 compiler,
934 env()->comp_level(),
935 has_unsafe_access(),
936 SharedRuntime::is_wide_vector(max_vector_size()),
937 rtm_state()
938 );
939
940 if (log() != NULL) // Print code cache state into compiler log
941 log()->code_cache_state();
942 }
943 }
944
945 //------------------------------Compile----------------------------------------
946 // Compile a runtime stub
947 Compile::Compile( ciEnv* ci_env,
948 TypeFunc_generator generator,
949 address stub_function,
950 const char *stub_name,
951 int is_fancy_jump,
952 bool pass_tls,
953 bool save_arg_registers,
954 bool return_pc )
955 : Phase(Compiler),
956 _env(ci_env),
957 _log(ci_env->log()),
958 _compile_id(0),
959 _save_argument_registers(save_arg_registers),
960 _method(NULL),
961 _stub_name(stub_name),
962 _stub_function(stub_function),
963 _stub_entry_point(NULL),
964 _entry_bci(InvocationEntryBci),
965 _initial_gvn(NULL),
966 _for_igvn(NULL),
967 _warm_calls(NULL),
968 _orig_pc_slot(0),
969 _orig_pc_slot_offset_in_bytes(0),
970 _subsume_loads(true),
971 _do_escape_analysis(false),
972 _eliminate_boxing(false),
973 _failure_reason(NULL),
974 _code_buffer("Compile::Fill_buffer"),
975 _has_method_handle_invokes(false),
976 _mach_constant_base_node(NULL),
977 _node_bundling_limit(0),
978 _node_bundling_base(NULL),
979 _java_calls(0),
980 _inner_loops(0),
981 #ifndef PRODUCT
982 _trace_opto_output(TraceOptoOutput),
983 _in_dump_cnt(0),
984 _printer(NULL),
985 #endif
986 _comp_arena(mtCompiler),
987 _node_arena(mtCompiler),
988 _old_arena(mtCompiler),
989 _Compile_types(mtCompiler),
990 _dead_node_list(comp_arena()),
991 _dead_node_count(0),
992 _congraph(NULL),
993 _replay_inline_data(NULL),
994 _number_of_mh_late_inlines(0),
995 _inlining_progress(false),
996 _inlining_incrementally(false),
997 _print_inlining_list(NULL),
998 _print_inlining_idx(0),
999 _allowed_reasons(0),
1000 _interpreter_frame_size(0),
1001 _max_node_limit(MaxNodeLimit) {
1002 C = this;
1003
1004 #ifndef PRODUCT
1005 TraceTime t1(NULL, &_t_totalCompilation, TimeCompiler, false);
1006 TraceTime t2(NULL, &_t_stubCompilation, TimeCompiler, false);
1007 set_print_assembly(PrintFrameConverterAssembly);
1008 set_parsed_irreducible_loop(false);
1009 #endif
1010 set_has_irreducible_loop(false); // no loops
1011
1012 CompileWrapper cw(this);
1013 Init(/*AliasLevel=*/ 0);
1014 init_tf((*generator)());
1015
1016 {
1017 // The following is a dummy for the sake of GraphKit::gen_stub
1018 Unique_Node_List for_igvn(comp_arena());
1019 set_for_igvn(&for_igvn); // not used, but some GraphKit guys push on this
1020 PhaseGVN gvn(Thread::current()->resource_area(),255);
1021 set_initial_gvn(&gvn); // not significant, but GraphKit guys use it pervasively
1022 gvn.transform_no_reclaim(top());
1023
1024 GraphKit kit;
1025 kit.gen_stub(stub_function, stub_name, is_fancy_jump, pass_tls, return_pc);
1026 }
1027
1028 NOT_PRODUCT( verify_graph_edges(); )
1029 Code_Gen();
1030 if (failing()) return;
1031
1032
1033 // Entry point will be accessed using compile->stub_entry_point();
1034 if (code_buffer() == NULL) {
1035 Matcher::soft_match_failure();
1036 } else {
1037 if (PrintAssembly && (WizardMode || Verbose))
1038 tty->print_cr("### Stub::%s", stub_name);
1039
1040 if (!failing()) {
1041 assert(_fixed_slots == 0, "no fixed slots used for runtime stubs");
1042
1043 // Make the NMethod
1044 // For now we mark the frame as never safe for profile stackwalking
1045 RuntimeStub *rs = RuntimeStub::new_runtime_stub(stub_name,
1046 code_buffer(),
1047 CodeOffsets::frame_never_safe,
1048 // _code_offsets.value(CodeOffsets::Frame_Complete),
1049 frame_size_in_words(),
1050 _oop_map_set,
1051 save_arg_registers);
1052 assert(rs != NULL && rs->is_runtime_stub(), "sanity check");
1053
1054 _stub_entry_point = rs->entry_point();
1055 }
1056 }
1057 }
1058
1059 //------------------------------Init-------------------------------------------
1060 // Prepare for a single compilation
1061 void Compile::Init(int aliaslevel) {
1062 _unique = 0;
1063 _regalloc = NULL;
1064
1065 _tf = NULL; // filled in later
1066 _top = NULL; // cached later
1067 _matcher = NULL; // filled in later
1068 _cfg = NULL; // filled in later
1069
1070 set_24_bit_selection_and_mode(Use24BitFP, false);
1071
1072 _node_note_array = NULL;
1073 _default_node_notes = NULL;
1074
1075 _immutable_memory = NULL; // filled in at first inquiry
1076
1077 // Globally visible Nodes
1078 // First set TOP to NULL to give safe behavior during creation of RootNode
1079 set_cached_top_node(NULL);
1080 set_root(new (this) RootNode());
1081 // Now that you have a Root to point to, create the real TOP
1082 set_cached_top_node( new (this) ConNode(Type::TOP) );
1083 set_recent_alloc(NULL, NULL);
1084
1085 // Create Debug Information Recorder to record scopes, oopmaps, etc.
1086 env()->set_oop_recorder(new OopRecorder(env()->arena()));
1087 env()->set_debug_info(new DebugInformationRecorder(env()->oop_recorder()));
1088 env()->set_dependencies(new Dependencies(env()));
1089
1090 _fixed_slots = 0;
1091 set_has_split_ifs(false);
1092 set_has_loops(has_method() && method()->has_loops()); // first approximation
1093 set_has_stringbuilder(false);
1094 set_has_boxed_value(false);
1095 _trap_can_recompile = false; // no traps emitted yet
1096 _major_progress = true; // start out assuming good things will happen
1097 set_has_unsafe_access(false);
1098 set_max_vector_size(0);
1099 Copy::zero_to_bytes(_trap_hist, sizeof(_trap_hist));
1100 set_decompile_count(0);
1101
1102 set_do_freq_based_layout(BlockLayoutByFrequency || method_has_option("BlockLayoutByFrequency"));
1103 set_num_loop_opts(LoopOptsCount);
1104 set_do_inlining(Inline);
1105 set_max_inline_size(MaxInlineSize);
1106 set_freq_inline_size(FreqInlineSize);
1107 set_do_scheduling(OptoScheduling);
1108 set_do_count_invocations(false);
1109 set_do_method_data_update(false);
1110 set_rtm_state(NoRTM); // No RTM lock eliding by default
1111 method_has_option_value("MaxNodeLimit", _max_node_limit);
1112 #if INCLUDE_RTM_OPT
1113 if (UseRTMLocking && has_method() && (method()->method_data_or_null() != NULL)) {
1114 int rtm_state = method()->method_data()->rtm_state();
1115 if (method_has_option("NoRTMLockEliding") || ((rtm_state & NoRTM) != 0)) {
1116 // Don't generate RTM lock eliding code.
1117 set_rtm_state(NoRTM);
1118 } else if (method_has_option("UseRTMLockEliding") || ((rtm_state & UseRTM) != 0) || !UseRTMDeopt) {
1119 // Generate RTM lock eliding code without abort ratio calculation code.
1120 set_rtm_state(UseRTM);
1121 } else if (UseRTMDeopt) {
1122 // Generate RTM lock eliding code and include abort ratio calculation
1123 // code if UseRTMDeopt is on.
1124 set_rtm_state(ProfileRTM);
1125 }
1126 }
1127 #endif
1128 if (debug_info()->recording_non_safepoints()) {
1129 set_node_note_array(new(comp_arena()) GrowableArray<Node_Notes*>
1130 (comp_arena(), 8, 0, NULL));
1131 set_default_node_notes(Node_Notes::make(this));
1132 }
1133
1134 // // -- Initialize types before each compile --
1135 // // Update cached type information
1136 // if( _method && _method->constants() )
1137 // Type::update_loaded_types(_method, _method->constants());
1138
1139 // Init alias_type map.
1140 if (!_do_escape_analysis && aliaslevel == 3)
1141 aliaslevel = 2; // No unique types without escape analysis
1142 _AliasLevel = aliaslevel;
1143 const int grow_ats = 16;
1144 _max_alias_types = grow_ats;
1145 _alias_types = NEW_ARENA_ARRAY(comp_arena(), AliasType*, grow_ats);
1146 AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType, grow_ats);
1147 Copy::zero_to_bytes(ats, sizeof(AliasType)*grow_ats);
1148 {
1149 for (int i = 0; i < grow_ats; i++) _alias_types[i] = &ats[i];
1150 }
1151 // Initialize the first few types.
1152 _alias_types[AliasIdxTop]->Init(AliasIdxTop, NULL);
1153 _alias_types[AliasIdxBot]->Init(AliasIdxBot, TypePtr::BOTTOM);
1154 _alias_types[AliasIdxRaw]->Init(AliasIdxRaw, TypeRawPtr::BOTTOM);
1155 _num_alias_types = AliasIdxRaw+1;
1156 // Zero out the alias type cache.
1157 Copy::zero_to_bytes(_alias_cache, sizeof(_alias_cache));
1158 // A NULL adr_type hits in the cache right away. Preload the right answer.
1159 probe_alias_cache(NULL)->_index = AliasIdxTop;
1160
1161 _intrinsics = NULL;
1162 _macro_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
1163 _predicate_opaqs = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
1164 _expensive_nodes = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
1165 _range_check_casts = new(comp_arena()) GrowableArray<Node*>(comp_arena(), 8, 0, NULL);
1166 register_library_intrinsics();
1167 }
1168
1169 //---------------------------init_start----------------------------------------
1170 // Install the StartNode on this compile object.
1171 void Compile::init_start(StartNode* s) {
1172 if (failing())
1173 return; // already failing
1174 assert(s == start(), "");
1175 }
1176
1177 StartNode* Compile::start() const {
1178 assert(!failing(), "");
1179 for (DUIterator_Fast imax, i = root()->fast_outs(imax); i < imax; i++) {
1180 Node* start = root()->fast_out(i);
1181 if( start->is_Start() )
1182 return start->as_Start();
1183 }
1184 fatal("Did not find Start node!");
1185 return NULL;
1186 }
1187
1188 //-------------------------------immutable_memory-------------------------------------
1189 // Access immutable memory
1190 Node* Compile::immutable_memory() {
1191 if (_immutable_memory != NULL) {
1192 return _immutable_memory;
1193 }
1194 StartNode* s = start();
1195 for (DUIterator_Fast imax, i = s->fast_outs(imax); true; i++) {
1196 Node *p = s->fast_out(i);
1197 if (p != s && p->as_Proj()->_con == TypeFunc::Memory) {
1198 _immutable_memory = p;
1199 return _immutable_memory;
1200 }
1201 }
1202 ShouldNotReachHere();
1203 return NULL;
1204 }
1205
1206 //----------------------set_cached_top_node------------------------------------
1207 // Install the cached top node, and make sure Node::is_top works correctly.
1208 void Compile::set_cached_top_node(Node* tn) {
1209 if (tn != NULL) verify_top(tn);
1210 Node* old_top = _top;
1211 _top = tn;
1212 // Calling Node::setup_is_top allows the nodes the chance to adjust
1213 // their _out arrays.
1214 if (_top != NULL) _top->setup_is_top();
1215 if (old_top != NULL) old_top->setup_is_top();
1216 assert(_top == NULL || top()->is_top(), "");
1217 }
1218
1219 #ifdef ASSERT
1220 uint Compile::count_live_nodes_by_graph_walk() {
1221 Unique_Node_List useful(comp_arena());
1222 // Get useful node list by walking the graph.
1223 identify_useful_nodes(useful);
1224 return useful.size();
1225 }
1226
1227 void Compile::print_missing_nodes() {
1228
1229 // Return if CompileLog is NULL and PrintIdealNodeCount is false.
1230 if ((_log == NULL) && (! PrintIdealNodeCount)) {
1231 return;
1232 }
1233
1234 // This is an expensive function. It is executed only when the user
1235 // specifies VerifyIdealNodeCount option or otherwise knows the
1236 // additional work that needs to be done to identify reachable nodes
1237 // by walking the flow graph and find the missing ones using
1238 // _dead_node_list.
1239
1240 Unique_Node_List useful(comp_arena());
1241 // Get useful node list by walking the graph.
1242 identify_useful_nodes(useful);
1243
1244 uint l_nodes = C->live_nodes();
1245 uint l_nodes_by_walk = useful.size();
1246
1247 if (l_nodes != l_nodes_by_walk) {
1248 if (_log != NULL) {
1249 _log->begin_head("mismatched_nodes count='%d'", abs((int) (l_nodes - l_nodes_by_walk)));
1250 _log->stamp();
1251 _log->end_head();
1252 }
1253 VectorSet& useful_member_set = useful.member_set();
1254 int last_idx = l_nodes_by_walk;
1255 for (int i = 0; i < last_idx; i++) {
1256 if (useful_member_set.test(i)) {
1257 if (_dead_node_list.test(i)) {
1258 if (_log != NULL) {
1259 _log->elem("mismatched_node_info node_idx='%d' type='both live and dead'", i);
1260 }
1261 if (PrintIdealNodeCount) {
1262 // Print the log message to tty
1263 tty->print_cr("mismatched_node idx='%d' both live and dead'", i);
1264 useful.at(i)->dump();
1265 }
1266 }
1267 }
1268 else if (! _dead_node_list.test(i)) {
1269 if (_log != NULL) {
1270 _log->elem("mismatched_node_info node_idx='%d' type='neither live nor dead'", i);
1271 }
1272 if (PrintIdealNodeCount) {
1273 // Print the log message to tty
1274 tty->print_cr("mismatched_node idx='%d' type='neither live nor dead'", i);
1275 }
1276 }
1277 }
1278 if (_log != NULL) {
1279 _log->tail("mismatched_nodes");
1280 }
1281 }
1282 }
1283 #endif
1284
1285 #ifndef PRODUCT
1286 void Compile::verify_top(Node* tn) const {
1287 if (tn != NULL) {
1288 assert(tn->is_Con(), "top node must be a constant");
1289 assert(((ConNode*)tn)->type() == Type::TOP, "top node must have correct type");
1290 assert(tn->in(0) != NULL, "must have live top node");
1291 }
1292 }
1293 #endif
1294
1295
1296 ///-------------------Managing Per-Node Debug & Profile Info-------------------
1297
1298 void Compile::grow_node_notes(GrowableArray<Node_Notes*>* arr, int grow_by) {
1299 guarantee(arr != NULL, "");
1300 int num_blocks = arr->length();
1301 if (grow_by < num_blocks) grow_by = num_blocks;
1302 int num_notes = grow_by * _node_notes_block_size;
1303 Node_Notes* notes = NEW_ARENA_ARRAY(node_arena(), Node_Notes, num_notes);
1304 Copy::zero_to_bytes(notes, num_notes * sizeof(Node_Notes));
1305 while (num_notes > 0) {
1306 arr->append(notes);
1307 notes += _node_notes_block_size;
1308 num_notes -= _node_notes_block_size;
1309 }
1310 assert(num_notes == 0, "exact multiple, please");
1311 }
1312
1313 bool Compile::copy_node_notes_to(Node* dest, Node* source) {
1314 if (source == NULL || dest == NULL) return false;
1315
1316 if (dest->is_Con())
1317 return false; // Do not push debug info onto constants.
1318
1319 #ifdef ASSERT
1320 // Leave a bread crumb trail pointing to the original node:
1321 if (dest != NULL && dest != source && dest->debug_orig() == NULL) {
1322 dest->set_debug_orig(source);
1323 }
1324 #endif
1325
1326 if (node_note_array() == NULL)
1327 return false; // Not collecting any notes now.
1328
1329 // This is a copy onto a pre-existing node, which may already have notes.
1330 // If both nodes have notes, do not overwrite any pre-existing notes.
1331 Node_Notes* source_notes = node_notes_at(source->_idx);
1332 if (source_notes == NULL || source_notes->is_clear()) return false;
1333 Node_Notes* dest_notes = node_notes_at(dest->_idx);
1334 if (dest_notes == NULL || dest_notes->is_clear()) {
1335 return set_node_notes_at(dest->_idx, source_notes);
1336 }
1337
1338 Node_Notes merged_notes = (*source_notes);
1339 // The order of operations here ensures that dest notes will win...
1340 merged_notes.update_from(dest_notes);
1341 return set_node_notes_at(dest->_idx, &merged_notes);
1342 }
1343
1344
1345 //--------------------------allow_range_check_smearing-------------------------
1346 // Gating condition for coalescing similar range checks.
1347 // Sometimes we try 'speculatively' replacing a series of a range checks by a
1348 // single covering check that is at least as strong as any of them.
1349 // If the optimization succeeds, the simplified (strengthened) range check
1350 // will always succeed. If it fails, we will deopt, and then give up
1351 // on the optimization.
1352 bool Compile::allow_range_check_smearing() const {
1353 // If this method has already thrown a range-check,
1354 // assume it was because we already tried range smearing
1355 // and it failed.
1356 uint already_trapped = trap_count(Deoptimization::Reason_range_check);
1357 return !already_trapped;
1358 }
1359
1360
1361 //------------------------------flatten_alias_type-----------------------------
1362 const TypePtr *Compile::flatten_alias_type( const TypePtr *tj ) const {
1363 int offset = tj->offset();
1364 TypePtr::PTR ptr = tj->ptr();
1365
1366 // Known instance (scalarizable allocation) alias only with itself.
1367 bool is_known_inst = tj->isa_oopptr() != NULL &&
1368 tj->is_oopptr()->is_known_instance();
1369
1370 // Process weird unsafe references.
1371 if (offset == Type::OffsetBot && (tj->isa_instptr() /*|| tj->isa_klassptr()*/)) {
1372 assert(InlineUnsafeOps, "indeterminate pointers come only from unsafe ops");
1373 assert(!is_known_inst, "scalarizable allocation should not have unsafe references");
1374 tj = TypeOopPtr::BOTTOM;
1375 ptr = tj->ptr();
1376 offset = tj->offset();
1377 }
1378
1379 // Array pointers need some flattening
1380 const TypeAryPtr *ta = tj->isa_aryptr();
1381 if (ta && ta->is_stable()) {
1382 // Erase stability property for alias analysis.
1383 tj = ta = ta->cast_to_stable(false);
1384 }
1385 if( ta && is_known_inst ) {
1386 if ( offset != Type::OffsetBot &&
1387 offset > arrayOopDesc::length_offset_in_bytes() ) {
1388 offset = Type::OffsetBot; // Flatten constant access into array body only
1389 tj = ta = TypeAryPtr::make(ptr, ta->ary(), ta->klass(), true, offset, ta->instance_id());
1390 }
1391 } else if( ta && _AliasLevel >= 2 ) {
1392 // For arrays indexed by constant indices, we flatten the alias
1393 // space to include all of the array body. Only the header, klass
1394 // and array length can be accessed un-aliased.
1395 if( offset != Type::OffsetBot ) {
1396 if( ta->const_oop() ) { // MethodData* or Method*
1397 offset = Type::OffsetBot; // Flatten constant access into array body
1398 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),ta->ary(),ta->klass(),false,offset);
1399 } else if( offset == arrayOopDesc::length_offset_in_bytes() ) {
1400 // range is OK as-is.
1401 tj = ta = TypeAryPtr::RANGE;
1402 } else if( offset == oopDesc::klass_offset_in_bytes() ) {
1403 tj = TypeInstPtr::KLASS; // all klass loads look alike
1404 ta = TypeAryPtr::RANGE; // generic ignored junk
1405 ptr = TypePtr::BotPTR;
1406 } else if( offset == oopDesc::mark_offset_in_bytes() ) {
1407 tj = TypeInstPtr::MARK;
1408 ta = TypeAryPtr::RANGE; // generic ignored junk
1409 ptr = TypePtr::BotPTR;
1410 } else { // Random constant offset into array body
1411 offset = Type::OffsetBot; // Flatten constant access into array body
1412 tj = ta = TypeAryPtr::make(ptr,ta->ary(),ta->klass(),false,offset);
1413 }
1414 }
1415 // Arrays of fixed size alias with arrays of unknown size.
1416 if (ta->size() != TypeInt::POS) {
1417 const TypeAry *tary = TypeAry::make(ta->elem(), TypeInt::POS);
1418 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,ta->klass(),false,offset);
1419 }
1420 // Arrays of known objects become arrays of unknown objects.
1421 if (ta->elem()->isa_narrowoop() && ta->elem() != TypeNarrowOop::BOTTOM) {
1422 const TypeAry *tary = TypeAry::make(TypeNarrowOop::BOTTOM, ta->size());
1423 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1424 }
1425 if (ta->elem()->isa_oopptr() && ta->elem() != TypeInstPtr::BOTTOM) {
1426 const TypeAry *tary = TypeAry::make(TypeInstPtr::BOTTOM, ta->size());
1427 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,NULL,false,offset);
1428 }
1429 // Arrays of bytes and of booleans both use 'bastore' and 'baload' so
1430 // cannot be distinguished by bytecode alone.
1431 if (ta->elem() == TypeInt::BOOL) {
1432 const TypeAry *tary = TypeAry::make(TypeInt::BYTE, ta->size());
1433 ciKlass* aklass = ciTypeArrayKlass::make(T_BYTE);
1434 tj = ta = TypeAryPtr::make(ptr,ta->const_oop(),tary,aklass,false,offset);
1435 }
1436 // During the 2nd round of IterGVN, NotNull castings are removed.
1437 // Make sure the Bottom and NotNull variants alias the same.
1438 // Also, make sure exact and non-exact variants alias the same.
1439 if (ptr == TypePtr::NotNull || ta->klass_is_exact() || ta->speculative() != NULL) {
1440 tj = ta = TypeAryPtr::make(TypePtr::BotPTR,ta->ary(),ta->klass(),false,offset);
1441 }
1442 }
1443
1444 // Oop pointers need some flattening
1445 const TypeInstPtr *to = tj->isa_instptr();
1446 if( to && _AliasLevel >= 2 && to != TypeOopPtr::BOTTOM ) {
1447 ciInstanceKlass *k = to->klass()->as_instance_klass();
1448 if( ptr == TypePtr::Constant ) {
1449 if (to->klass() != ciEnv::current()->Class_klass() ||
1450 offset < k->size_helper() * wordSize) {
1451 // No constant oop pointers (such as Strings); they alias with
1452 // unknown strings.
1453 assert(!is_known_inst, "not scalarizable allocation");
1454 tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1455 }
1456 } else if( is_known_inst ) {
1457 tj = to; // Keep NotNull and klass_is_exact for instance type
1458 } else if( ptr == TypePtr::NotNull || to->klass_is_exact() ) {
1459 // During the 2nd round of IterGVN, NotNull castings are removed.
1460 // Make sure the Bottom and NotNull variants alias the same.
1461 // Also, make sure exact and non-exact variants alias the same.
1462 tj = to = TypeInstPtr::make(TypePtr::BotPTR,to->klass(),false,0,offset);
1463 }
1464 if (to->speculative() != NULL) {
1465 tj = to = TypeInstPtr::make(to->ptr(),to->klass(),to->klass_is_exact(),to->const_oop(),to->offset(), to->instance_id());
1466 }
1467 // Canonicalize the holder of this field
1468 if (offset >= 0 && offset < instanceOopDesc::base_offset_in_bytes()) {
1469 // First handle header references such as a LoadKlassNode, even if the
1470 // object's klass is unloaded at compile time (4965979).
1471 if (!is_known_inst) { // Do it only for non-instance types
1472 tj = to = TypeInstPtr::make(TypePtr::BotPTR, env()->Object_klass(), false, NULL, offset);
1473 }
1474 } else if (offset < 0 || offset >= k->size_helper() * wordSize) {
1475 // Static fields are in the space above the normal instance
1476 // fields in the java.lang.Class instance.
1477 if (to->klass() != ciEnv::current()->Class_klass()) {
1478 to = NULL;
1479 tj = TypeOopPtr::BOTTOM;
1480 offset = tj->offset();
1481 }
1482 } else {
1483 ciInstanceKlass *canonical_holder = k->get_canonical_holder(offset);
1484 if (!k->equals(canonical_holder) || tj->offset() != offset) {
1485 if( is_known_inst ) {
1486 tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, true, NULL, offset, to->instance_id());
1487 } else {
1488 tj = to = TypeInstPtr::make(to->ptr(), canonical_holder, false, NULL, offset);
1489 }
1490 }
1491 }
1492 }
1493
1494 // Klass pointers to object array klasses need some flattening
1495 const TypeKlassPtr *tk = tj->isa_klassptr();
1496 if( tk ) {
1497 // If we are referencing a field within a Klass, we need
1498 // to assume the worst case of an Object. Both exact and
1499 // inexact types must flatten to the same alias class so
1500 // use NotNull as the PTR.
1501 if ( offset == Type::OffsetBot || (offset >= 0 && (size_t)offset < sizeof(Klass)) ) {
1502
1503 tj = tk = TypeKlassPtr::make(TypePtr::NotNull,
1504 TypeKlassPtr::OBJECT->klass(),
1505 offset);
1506 }
1507
1508 ciKlass* klass = tk->klass();
1509 if( klass->is_obj_array_klass() ) {
1510 ciKlass* k = TypeAryPtr::OOPS->klass();
1511 if( !k || !k->is_loaded() ) // Only fails for some -Xcomp runs
1512 k = TypeInstPtr::BOTTOM->klass();
1513 tj = tk = TypeKlassPtr::make( TypePtr::NotNull, k, offset );
1514 }
1515
1516 // Check for precise loads from the primary supertype array and force them
1517 // to the supertype cache alias index. Check for generic array loads from
1518 // the primary supertype array and also force them to the supertype cache
1519 // alias index. Since the same load can reach both, we need to merge
1520 // these 2 disparate memories into the same alias class. Since the
1521 // primary supertype array is read-only, there's no chance of confusion
1522 // where we bypass an array load and an array store.
1523 int primary_supers_offset = in_bytes(Klass::primary_supers_offset());
1524 if (offset == Type::OffsetBot ||
1525 (offset >= primary_supers_offset &&
1526 offset < (int)(primary_supers_offset + Klass::primary_super_limit() * wordSize)) ||
1527 offset == (int)in_bytes(Klass::secondary_super_cache_offset())) {
1528 offset = in_bytes(Klass::secondary_super_cache_offset());
1529 tj = tk = TypeKlassPtr::make( TypePtr::NotNull, tk->klass(), offset );
1530 }
1531 }
1532
1533 // Flatten all Raw pointers together.
1534 if (tj->base() == Type::RawPtr)
1535 tj = TypeRawPtr::BOTTOM;
1536
1537 if (tj->base() == Type::AnyPtr)
1538 tj = TypePtr::BOTTOM; // An error, which the caller must check for.
1539
1540 // Flatten all to bottom for now
1541 switch( _AliasLevel ) {
1542 case 0:
1543 tj = TypePtr::BOTTOM;
1544 break;
1545 case 1: // Flatten to: oop, static, field or array
1546 switch (tj->base()) {
1547 //case Type::AryPtr: tj = TypeAryPtr::RANGE; break;
1548 case Type::RawPtr: tj = TypeRawPtr::BOTTOM; break;
1549 case Type::AryPtr: // do not distinguish arrays at all
1550 case Type::InstPtr: tj = TypeInstPtr::BOTTOM; break;
1551 case Type::KlassPtr: tj = TypeKlassPtr::OBJECT; break;
1552 case Type::AnyPtr: tj = TypePtr::BOTTOM; break; // caller checks it
1553 default: ShouldNotReachHere();
1554 }
1555 break;
1556 case 2: // No collapsing at level 2; keep all splits
1557 case 3: // No collapsing at level 3; keep all splits
1558 break;
1559 default:
1560 Unimplemented();
1561 }
1562
1563 offset = tj->offset();
1564 assert( offset != Type::OffsetTop, "Offset has fallen from constant" );
1565
1566 assert( (offset != Type::OffsetBot && tj->base() != Type::AryPtr) ||
1567 (offset == Type::OffsetBot && tj->base() == Type::AryPtr) ||
1568 (offset == Type::OffsetBot && tj == TypeOopPtr::BOTTOM) ||
1569 (offset == Type::OffsetBot && tj == TypePtr::BOTTOM) ||
1570 (offset == oopDesc::mark_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1571 (offset == oopDesc::klass_offset_in_bytes() && tj->base() == Type::AryPtr) ||
1572 (offset == arrayOopDesc::length_offset_in_bytes() && tj->base() == Type::AryPtr) ,
1573 "For oops, klasses, raw offset must be constant; for arrays the offset is never known" );
1574 assert( tj->ptr() != TypePtr::TopPTR &&
1575 tj->ptr() != TypePtr::AnyNull &&
1576 tj->ptr() != TypePtr::Null, "No imprecise addresses" );
1577 // assert( tj->ptr() != TypePtr::Constant ||
1578 // tj->base() == Type::RawPtr ||
1579 // tj->base() == Type::KlassPtr, "No constant oop addresses" );
1580
1581 return tj;
1582 }
1583
1584 void Compile::AliasType::Init(int i, const TypePtr* at) {
1585 _index = i;
1586 _adr_type = at;
1587 _field = NULL;
1588 _element = NULL;
1589 _is_rewritable = true; // default
1590 const TypeOopPtr *atoop = (at != NULL) ? at->isa_oopptr() : NULL;
1591 if (atoop != NULL && atoop->is_known_instance()) {
1592 const TypeOopPtr *gt = atoop->cast_to_instance_id(TypeOopPtr::InstanceBot);
1593 _general_index = Compile::current()->get_alias_index(gt);
1594 } else {
1595 _general_index = 0;
1596 }
1597 }
1598
1599 BasicType Compile::AliasType::basic_type() const {
1600 if (element() != NULL) {
1601 const Type* element = adr_type()->is_aryptr()->elem();
1602 return element->isa_narrowoop() ? T_OBJECT : element->array_element_basic_type();
1603 } if (field() != NULL) {
1604 return field()->layout_type();
1605 } else {
1606 return T_ILLEGAL; // unknown
1607 }
1608 }
1609
1610 //---------------------------------print_on------------------------------------
1611 #ifndef PRODUCT
1612 void Compile::AliasType::print_on(outputStream* st) {
1613 if (index() < 10)
1614 st->print("@ <%d> ", index());
1615 else st->print("@ <%d>", index());
1616 st->print(is_rewritable() ? " " : " RO");
1617 int offset = adr_type()->offset();
1618 if (offset == Type::OffsetBot)
1619 st->print(" +any");
1620 else st->print(" +%-3d", offset);
1621 st->print(" in ");
1622 adr_type()->dump_on(st);
1623 const TypeOopPtr* tjp = adr_type()->isa_oopptr();
1624 if (field() != NULL && tjp) {
1625 if (tjp->klass() != field()->holder() ||
1626 tjp->offset() != field()->offset_in_bytes()) {
1627 st->print(" != ");
1628 field()->print();
1629 st->print(" ***");
1630 }
1631 }
1632 }
1633
1634 void print_alias_types() {
1635 Compile* C = Compile::current();
1636 tty->print_cr("--- Alias types, AliasIdxBot .. %d", C->num_alias_types()-1);
1637 for (int idx = Compile::AliasIdxBot; idx < C->num_alias_types(); idx++) {
1638 C->alias_type(idx)->print_on(tty);
1639 tty->cr();
1640 }
1641 }
1642 #endif
1643
1644
1645 //----------------------------probe_alias_cache--------------------------------
1646 Compile::AliasCacheEntry* Compile::probe_alias_cache(const TypePtr* adr_type) {
1647 intptr_t key = (intptr_t) adr_type;
1648 key ^= key >> logAliasCacheSize;
1649 return &_alias_cache[key & right_n_bits(logAliasCacheSize)];
1650 }
1651
1652
1653 //-----------------------------grow_alias_types--------------------------------
1654 void Compile::grow_alias_types() {
1655 const int old_ats = _max_alias_types; // how many before?
1656 const int new_ats = old_ats; // how many more?
1657 const int grow_ats = old_ats+new_ats; // how many now?
1658 _max_alias_types = grow_ats;
1659 _alias_types = REALLOC_ARENA_ARRAY(comp_arena(), AliasType*, _alias_types, old_ats, grow_ats);
1660 AliasType* ats = NEW_ARENA_ARRAY(comp_arena(), AliasType, new_ats);
1661 Copy::zero_to_bytes(ats, sizeof(AliasType)*new_ats);
1662 for (int i = 0; i < new_ats; i++) _alias_types[old_ats+i] = &ats[i];
1663 }
1664
1665
1666 //--------------------------------find_alias_type------------------------------
1667 Compile::AliasType* Compile::find_alias_type(const TypePtr* adr_type, bool no_create, ciField* original_field) {
1668 if (_AliasLevel == 0)
1669 return alias_type(AliasIdxBot);
1670
1671 AliasCacheEntry* ace = probe_alias_cache(adr_type);
1672 if (ace->_adr_type == adr_type) {
1673 return alias_type(ace->_index);
1674 }
1675
1676 // Handle special cases.
1677 if (adr_type == NULL) return alias_type(AliasIdxTop);
1678 if (adr_type == TypePtr::BOTTOM) return alias_type(AliasIdxBot);
1679
1680 // Do it the slow way.
1681 const TypePtr* flat = flatten_alias_type(adr_type);
1682
1683 #ifdef ASSERT
1684 {
1685 ResourceMark rm;
1686 assert(flat == flatten_alias_type(flat),
1687 err_msg("not idempotent: adr_type = %s; flat = %s => %s", Type::str(adr_type),
1688 Type::str(flat), Type::str(flatten_alias_type(flat))));
1689 assert(flat != TypePtr::BOTTOM,
1690 err_msg("cannot alias-analyze an untyped ptr: adr_type = %s", Type::str(adr_type)));
1691 if (flat->isa_oopptr() && !flat->isa_klassptr()) {
1692 const TypeOopPtr* foop = flat->is_oopptr();
1693 // Scalarizable allocations have exact klass always.
1694 bool exact = !foop->klass_is_exact() || foop->is_known_instance();
1695 const TypePtr* xoop = foop->cast_to_exactness(exact)->is_ptr();
1696 assert(foop == flatten_alias_type(xoop),
1697 err_msg("exactness must not affect alias type: foop = %s; xoop = %s",
1698 Type::str(foop), Type::str(xoop)));
1699 }
1700 }
1701 #endif
1702
1703 int idx = AliasIdxTop;
1704 for (int i = 0; i < num_alias_types(); i++) {
1705 if (alias_type(i)->adr_type() == flat) {
1706 idx = i;
1707 break;
1708 }
1709 }
1710
1711 if (idx == AliasIdxTop) {
1712 if (no_create) return NULL;
1713 // Grow the array if necessary.
1714 if (_num_alias_types == _max_alias_types) grow_alias_types();
1715 // Add a new alias type.
1716 idx = _num_alias_types++;
1717 _alias_types[idx]->Init(idx, flat);
1718 if (flat == TypeInstPtr::KLASS) alias_type(idx)->set_rewritable(false);
1719 if (flat == TypeAryPtr::RANGE) alias_type(idx)->set_rewritable(false);
1720 if (flat->isa_instptr()) {
1721 if (flat->offset() == java_lang_Class::klass_offset_in_bytes()
1722 && flat->is_instptr()->klass() == env()->Class_klass())
1723 alias_type(idx)->set_rewritable(false);
1724 }
1725 if (flat->isa_aryptr()) {
1726 #ifdef ASSERT
1727 const int header_size_min = arrayOopDesc::base_offset_in_bytes(T_BYTE);
1728 // (T_BYTE has the weakest alignment and size restrictions...)
1729 assert(flat->offset() < header_size_min, "array body reference must be OffsetBot");
1730 #endif
1731 if (flat->offset() == TypePtr::OffsetBot) {
1732 alias_type(idx)->set_element(flat->is_aryptr()->elem());
1733 }
1734 }
1735 if (flat->isa_klassptr()) {
1736 if (flat->offset() == in_bytes(Klass::super_check_offset_offset()))
1737 alias_type(idx)->set_rewritable(false);
1738 if (flat->offset() == in_bytes(Klass::modifier_flags_offset()))
1739 alias_type(idx)->set_rewritable(false);
1740 if (flat->offset() == in_bytes(Klass::access_flags_offset()))
1741 alias_type(idx)->set_rewritable(false);
1742 if (flat->offset() == in_bytes(Klass::java_mirror_offset()))
1743 alias_type(idx)->set_rewritable(false);
1744 }
1745 // %%% (We would like to finalize JavaThread::threadObj_offset(),
1746 // but the base pointer type is not distinctive enough to identify
1747 // references into JavaThread.)
1748
1749 // Check for final fields.
1750 const TypeInstPtr* tinst = flat->isa_instptr();
1751 if (tinst && tinst->offset() >= instanceOopDesc::base_offset_in_bytes()) {
1752 ciField* field;
1753 if (tinst->const_oop() != NULL &&
1754 tinst->klass() == ciEnv::current()->Class_klass() &&
1755 tinst->offset() >= (tinst->klass()->as_instance_klass()->size_helper() * wordSize)) {
1756 // static field
1757 ciInstanceKlass* k = tinst->const_oop()->as_instance()->java_lang_Class_klass()->as_instance_klass();
1758 field = k->get_field_by_offset(tinst->offset(), true);
1759 } else {
1760 ciInstanceKlass *k = tinst->klass()->as_instance_klass();
1761 field = k->get_field_by_offset(tinst->offset(), false);
1762 }
1763 assert(field == NULL ||
1764 original_field == NULL ||
1765 (field->holder() == original_field->holder() &&
1766 field->offset() == original_field->offset() &&
1767 field->is_static() == original_field->is_static()), "wrong field?");
1768 // Set field() and is_rewritable() attributes.
1769 if (field != NULL) alias_type(idx)->set_field(field);
1770 }
1771 }
1772
1773 // Fill the cache for next time.
1774 ace->_adr_type = adr_type;
1775 ace->_index = idx;
1776 assert(alias_type(adr_type) == alias_type(idx), "type must be installed");
1777
1778 // Might as well try to fill the cache for the flattened version, too.
1779 AliasCacheEntry* face = probe_alias_cache(flat);
1780 if (face->_adr_type == NULL) {
1781 face->_adr_type = flat;
1782 face->_index = idx;
1783 assert(alias_type(flat) == alias_type(idx), "flat type must work too");
1784 }
1785
1786 return alias_type(idx);
1787 }
1788
1789
1790 Compile::AliasType* Compile::alias_type(ciField* field) {
1791 const TypeOopPtr* t;
1792 if (field->is_static())
1793 t = TypeInstPtr::make(field->holder()->java_mirror());
1794 else
1795 t = TypeOopPtr::make_from_klass_raw(field->holder());
1796 AliasType* atp = alias_type(t->add_offset(field->offset_in_bytes()), field);
1797 assert((field->is_final() || field->is_stable()) == !atp->is_rewritable(), "must get the rewritable bits correct");
1798 return atp;
1799 }
1800
1801
1802 //------------------------------have_alias_type--------------------------------
1803 bool Compile::have_alias_type(const TypePtr* adr_type) {
1804 AliasCacheEntry* ace = probe_alias_cache(adr_type);
1805 if (ace->_adr_type == adr_type) {
1806 return true;
1807 }
1808
1809 // Handle special cases.
1810 if (adr_type == NULL) return true;
1811 if (adr_type == TypePtr::BOTTOM) return true;
1812
1813 return find_alias_type(adr_type, true, NULL) != NULL;
1814 }
1815
1816 //-----------------------------must_alias--------------------------------------
1817 // True if all values of the given address type are in the given alias category.
1818 bool Compile::must_alias(const TypePtr* adr_type, int alias_idx) {
1819 if (alias_idx == AliasIdxBot) return true; // the universal category
1820 if (adr_type == NULL) return true; // NULL serves as TypePtr::TOP
1821 if (alias_idx == AliasIdxTop) return false; // the empty category
1822 if (adr_type->base() == Type::AnyPtr) return false; // TypePtr::BOTTOM or its twins
1823
1824 // the only remaining possible overlap is identity
1825 int adr_idx = get_alias_index(adr_type);
1826 assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1827 assert(adr_idx == alias_idx ||
1828 (alias_type(alias_idx)->adr_type() != TypeOopPtr::BOTTOM
1829 && adr_type != TypeOopPtr::BOTTOM),
1830 "should not be testing for overlap with an unsafe pointer");
1831 return adr_idx == alias_idx;
1832 }
1833
1834 //------------------------------can_alias--------------------------------------
1835 // True if any values of the given address type are in the given alias category.
1836 bool Compile::can_alias(const TypePtr* adr_type, int alias_idx) {
1837 if (alias_idx == AliasIdxTop) return false; // the empty category
1838 if (adr_type == NULL) return false; // NULL serves as TypePtr::TOP
1839 if (alias_idx == AliasIdxBot) return true; // the universal category
1840 if (adr_type->base() == Type::AnyPtr) return true; // TypePtr::BOTTOM or its twins
1841
1842 // the only remaining possible overlap is identity
1843 int adr_idx = get_alias_index(adr_type);
1844 assert(adr_idx != AliasIdxBot && adr_idx != AliasIdxTop, "");
1845 return adr_idx == alias_idx;
1846 }
1847
1848
1849
1850 //---------------------------pop_warm_call-------------------------------------
1851 WarmCallInfo* Compile::pop_warm_call() {
1852 WarmCallInfo* wci = _warm_calls;
1853 if (wci != NULL) _warm_calls = wci->remove_from(wci);
1854 return wci;
1855 }
1856
1857 //----------------------------Inline_Warm--------------------------------------
1858 int Compile::Inline_Warm() {
1859 // If there is room, try to inline some more warm call sites.
1860 // %%% Do a graph index compaction pass when we think we're out of space?
1861 if (!InlineWarmCalls) return 0;
1862
1863 int calls_made_hot = 0;
1864 int room_to_grow = NodeCountInliningCutoff - unique();
1865 int amount_to_grow = MIN2(room_to_grow, (int)NodeCountInliningStep);
1866 int amount_grown = 0;
1867 WarmCallInfo* call;
1868 while (amount_to_grow > 0 && (call = pop_warm_call()) != NULL) {
1869 int est_size = (int)call->size();
1870 if (est_size > (room_to_grow - amount_grown)) {
1871 // This one won't fit anyway. Get rid of it.
1872 call->make_cold();
1873 continue;
1874 }
1875 call->make_hot();
1876 calls_made_hot++;
1877 amount_grown += est_size;
1878 amount_to_grow -= est_size;
1879 }
1880
1881 if (calls_made_hot > 0) set_major_progress();
1882 return calls_made_hot;
1883 }
1884
1885
1886 //----------------------------Finish_Warm--------------------------------------
1887 void Compile::Finish_Warm() {
1888 if (!InlineWarmCalls) return;
1889 if (failing()) return;
1890 if (warm_calls() == NULL) return;
1891
1892 // Clean up loose ends, if we are out of space for inlining.
1893 WarmCallInfo* call;
1894 while ((call = pop_warm_call()) != NULL) {
1895 call->make_cold();
1896 }
1897 }
1898
1899 //---------------------cleanup_loop_predicates-----------------------
1900 // Remove the opaque nodes that protect the predicates so that all unused
1901 // checks and uncommon_traps will be eliminated from the ideal graph
1902 void Compile::cleanup_loop_predicates(PhaseIterGVN &igvn) {
1903 if (predicate_count()==0) return;
1904 for (int i = predicate_count(); i > 0; i--) {
1905 Node * n = predicate_opaque1_node(i-1);
1906 assert(n->Opcode() == Op_Opaque1, "must be");
1907 igvn.replace_node(n, n->in(1));
1908 }
1909 assert(predicate_count()==0, "should be clean!");
1910 }
1911
1912 void Compile::add_range_check_cast(Node* n) {
1913 assert(n->isa_CastII()->has_range_check(), "CastII should have range check dependency");
1914 assert(!_range_check_casts->contains(n), "duplicate entry in range check casts");
1915 _range_check_casts->append(n);
1916 }
1917
1918 // Remove all range check dependent CastIINodes.
1919 void Compile::remove_range_check_casts(PhaseIterGVN &igvn) {
1920 for (int i = range_check_cast_count(); i > 0; i--) {
1921 Node* cast = range_check_cast_node(i-1);
1922 assert(cast->isa_CastII()->has_range_check(), "CastII should have range check dependency");
1923 igvn.replace_node(cast, cast->in(1));
1924 }
1925 assert(range_check_cast_count() == 0, "should be empty");
1926 }
1927
1928 // StringOpts and late inlining of string methods
1929 void Compile::inline_string_calls(bool parse_time) {
1930 {
1931 // remove useless nodes to make the usage analysis simpler
1932 ResourceMark rm;
1933 PhaseRemoveUseless pru(initial_gvn(), for_igvn());
1934 }
1935
1936 {
1937 ResourceMark rm;
1938 print_method(PHASE_BEFORE_STRINGOPTS, 3);
1939 PhaseStringOpts pso(initial_gvn(), for_igvn());
1940 print_method(PHASE_AFTER_STRINGOPTS, 3);
1941 }
1942
1943 // now inline anything that we skipped the first time around
1944 if (!parse_time) {
1945 _late_inlines_pos = _late_inlines.length();
1946 }
1947
1948 while (_string_late_inlines.length() > 0) {
1949 CallGenerator* cg = _string_late_inlines.pop();
1950 cg->do_late_inline();
1951 if (failing()) return;
1952 }
1953 _string_late_inlines.trunc_to(0);
1954 }
1955
1956 // Late inlining of boxing methods
1957 void Compile::inline_boxing_calls(PhaseIterGVN& igvn) {
1958 if (_boxing_late_inlines.length() > 0) {
1959 assert(has_boxed_value(), "inconsistent");
1960
1961 PhaseGVN* gvn = initial_gvn();
1962 set_inlining_incrementally(true);
1963
1964 assert( igvn._worklist.size() == 0, "should be done with igvn" );
1965 for_igvn()->clear();
1966 gvn->replace_with(&igvn);
1967
1968 _late_inlines_pos = _late_inlines.length();
1969
1970 while (_boxing_late_inlines.length() > 0) {
1971 CallGenerator* cg = _boxing_late_inlines.pop();
1972 cg->do_late_inline();
1973 if (failing()) return;
1974 }
1975 _boxing_late_inlines.trunc_to(0);
1976
1977 {
1978 ResourceMark rm;
1979 PhaseRemoveUseless pru(gvn, for_igvn());
1980 }
1981
1982 igvn = PhaseIterGVN(gvn);
1983 igvn.optimize();
1984
1985 set_inlining_progress(false);
1986 set_inlining_incrementally(false);
1987 }
1988 }
1989
1990 void Compile::inline_incrementally_one(PhaseIterGVN& igvn) {
1991 assert(IncrementalInline, "incremental inlining should be on");
1992 PhaseGVN* gvn = initial_gvn();
1993
1994 set_inlining_progress(false);
1995 for_igvn()->clear();
1996 gvn->replace_with(&igvn);
1997
1998 int i = 0;
1999
2000 for (; i <_late_inlines.length() && !inlining_progress(); i++) {
2001 CallGenerator* cg = _late_inlines.at(i);
2002 _late_inlines_pos = i+1;
2003 cg->do_late_inline();
2004 if (failing()) return;
2005 }
2006 int j = 0;
2007 for (; i < _late_inlines.length(); i++, j++) {
2008 _late_inlines.at_put(j, _late_inlines.at(i));
2009 }
2010 _late_inlines.trunc_to(j);
2011
2012 {
2013 ResourceMark rm;
2014 PhaseRemoveUseless pru(gvn, for_igvn());
2015 }
2016
2017 igvn = PhaseIterGVN(gvn);
2018 }
2019
2020 // Perform incremental inlining until bound on number of live nodes is reached
2021 void Compile::inline_incrementally(PhaseIterGVN& igvn) {
2022 PhaseGVN* gvn = initial_gvn();
2023
2024 set_inlining_incrementally(true);
2025 set_inlining_progress(true);
2026 uint low_live_nodes = 0;
2027
2028 while(inlining_progress() && _late_inlines.length() > 0) {
2029
2030 if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2031 if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
2032 // PhaseIdealLoop is expensive so we only try it once we are
2033 // out of live nodes and we only try it again if the previous
2034 // helped got the number of nodes down significantly
2035 PhaseIdealLoop ideal_loop( igvn, false, true );
2036 if (failing()) return;
2037 low_live_nodes = live_nodes();
2038 _major_progress = true;
2039 }
2040
2041 if (live_nodes() > (uint)LiveNodeCountInliningCutoff) {
2042 break;
2043 }
2044 }
2045
2046 inline_incrementally_one(igvn);
2047
2048 if (failing()) return;
2049
2050 igvn.optimize();
2051
2052 if (failing()) return;
2053 }
2054
2055 assert( igvn._worklist.size() == 0, "should be done with igvn" );
2056
2057 if (_string_late_inlines.length() > 0) {
2058 assert(has_stringbuilder(), "inconsistent");
2059 for_igvn()->clear();
2060 initial_gvn()->replace_with(&igvn);
2061
2062 inline_string_calls(false);
2063
2064 if (failing()) return;
2065
2066 {
2067 ResourceMark rm;
2068 PhaseRemoveUseless pru(initial_gvn(), for_igvn());
2069 }
2070
2071 igvn = PhaseIterGVN(gvn);
2072
2073 igvn.optimize();
2074 }
2075
2076 set_inlining_incrementally(false);
2077 }
2078
2079
2080 //------------------------------Optimize---------------------------------------
2081 // Given a graph, optimize it.
2082 void Compile::Optimize() {
2083 TracePhase t1("optimizer", &_t_optimizer, true);
2084
2085 #ifndef PRODUCT
2086 if (env()->break_at_compile()) {
2087 BREAKPOINT;
2088 }
2089
2090 #endif
2091
2092 ResourceMark rm;
2093 int loop_opts_cnt;
2094
2095 NOT_PRODUCT( verify_graph_edges(); )
2096
2097 print_method(PHASE_AFTER_PARSING);
2098
2099 {
2100 // Iterative Global Value Numbering, including ideal transforms
2101 // Initialize IterGVN with types and values from parse-time GVN
2102 PhaseIterGVN igvn(initial_gvn());
2103 {
2104 NOT_PRODUCT( TracePhase t2("iterGVN", &_t_iterGVN, TimeCompiler); )
2105 igvn.optimize();
2106 }
2107
2108 print_method(PHASE_ITER_GVN1, 2);
2109
2110 if (failing()) return;
2111
2112 {
2113 NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2114 inline_incrementally(igvn);
2115 }
2116
2117 print_method(PHASE_INCREMENTAL_INLINE, 2);
2118
2119 if (failing()) return;
2120
2121 if (eliminate_boxing()) {
2122 NOT_PRODUCT( TracePhase t2("incrementalInline", &_t_incrInline, TimeCompiler); )
2123 // Inline valueOf() methods now.
2124 inline_boxing_calls(igvn);
2125
2126 if (AlwaysIncrementalInline) {
2127 inline_incrementally(igvn);
2128 }
2129
2130 print_method(PHASE_INCREMENTAL_BOXING_INLINE, 2);
2131
2132 if (failing()) return;
2133 }
2134
2135 // Remove the speculative part of types and clean up the graph from
2136 // the extra CastPP nodes whose only purpose is to carry them. Do
2137 // that early so that optimizations are not disrupted by the extra
2138 // CastPP nodes.
2139 remove_speculative_types(igvn);
2140
2141 // No more new expensive nodes will be added to the list from here
2142 // so keep only the actual candidates for optimizations.
2143 cleanup_expensive_nodes(igvn);
2144
2145 if (!failing() && RenumberLiveNodes && live_nodes() + NodeLimitFudgeFactor < unique()) {
2146 NOT_PRODUCT(Compile::TracePhase t2("", &_t_renumberLive, TimeCompiler);)
2147 initial_gvn()->replace_with(&igvn);
2148 for_igvn()->clear();
2149 Unique_Node_List new_worklist(C->comp_arena());
2150 {
2151 ResourceMark rm;
2152 PhaseRenumberLive prl = PhaseRenumberLive(initial_gvn(), for_igvn(), &new_worklist);
2153 }
2154 set_for_igvn(&new_worklist);
2155 igvn = PhaseIterGVN(initial_gvn());
2156 igvn.optimize();
2157 }
2158
2159 // Perform escape analysis
2160 if (_do_escape_analysis && ConnectionGraph::has_candidates(this)) {
2161 if (has_loops()) {
2162 // Cleanup graph (remove dead nodes).
2163 TracePhase t2("idealLoop", &_t_idealLoop, true);
2164 PhaseIdealLoop ideal_loop( igvn, false, true );
2165 if (major_progress()) print_method(PHASE_PHASEIDEAL_BEFORE_EA, 2);
2166 if (failing()) return;
2167 }
2168 ConnectionGraph::do_analysis(this, &igvn);
2169
2170 if (failing()) return;
2171
2172 // Optimize out fields loads from scalar replaceable allocations.
2173 igvn.optimize();
2174 print_method(PHASE_ITER_GVN_AFTER_EA, 2);
2175
2176 if (failing()) return;
2177
2178 if (congraph() != NULL && macro_count() > 0) {
2179 NOT_PRODUCT( TracePhase t2("macroEliminate", &_t_macroEliminate, TimeCompiler); )
2180 PhaseMacroExpand mexp(igvn);
2181 mexp.eliminate_macro_nodes();
2182 igvn.set_delay_transform(false);
2183
2184 igvn.optimize();
2185 print_method(PHASE_ITER_GVN_AFTER_ELIMINATION, 2);
2186
2187 if (failing()) return;
2188 }
2189 }
2190
2191 // Loop transforms on the ideal graph. Range Check Elimination,
2192 // peeling, unrolling, etc.
2193
2194 // Set loop opts counter
2195 loop_opts_cnt = num_loop_opts();
2196 if((loop_opts_cnt > 0) && (has_loops() || has_split_ifs())) {
2197 {
2198 TracePhase t2("idealLoop", &_t_idealLoop, true);
2199 PhaseIdealLoop ideal_loop( igvn, true );
2200 loop_opts_cnt--;
2201 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP1, 2);
2202 if (failing()) return;
2203 }
2204 // Loop opts pass if partial peeling occurred in previous pass
2205 if(PartialPeelLoop && major_progress() && (loop_opts_cnt > 0)) {
2206 TracePhase t3("idealLoop", &_t_idealLoop, true);
2207 PhaseIdealLoop ideal_loop( igvn, false );
2208 loop_opts_cnt--;
2209 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP2, 2);
2210 if (failing()) return;
2211 }
2212 // Loop opts pass for loop-unrolling before CCP
2213 if(major_progress() && (loop_opts_cnt > 0)) {
2214 TracePhase t4("idealLoop", &_t_idealLoop, true);
2215 PhaseIdealLoop ideal_loop( igvn, false );
2216 loop_opts_cnt--;
2217 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP3, 2);
2218 }
2219 if (!failing()) {
2220 // Verify that last round of loop opts produced a valid graph
2221 NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2222 PhaseIdealLoop::verify(igvn);
2223 }
2224 }
2225 if (failing()) return;
2226
2227 // Conditional Constant Propagation;
2228 PhaseCCP ccp( &igvn );
2229 assert( true, "Break here to ccp.dump_nodes_and_types(_root,999,1)");
2230 {
2231 TracePhase t2("ccp", &_t_ccp, true);
2232 ccp.do_transform();
2233 }
2234 print_method(PHASE_CPP1, 2);
2235
2236 assert( true, "Break here to ccp.dump_old2new_map()");
2237
2238 // Iterative Global Value Numbering, including ideal transforms
2239 {
2240 NOT_PRODUCT( TracePhase t2("iterGVN2", &_t_iterGVN2, TimeCompiler); )
2241 igvn = ccp;
2242 igvn.optimize();
2243 }
2244
2245 print_method(PHASE_ITER_GVN2, 2);
2246
2247 if (failing()) return;
2248
2249 // Loop transforms on the ideal graph. Range Check Elimination,
2250 // peeling, unrolling, etc.
2251 if(loop_opts_cnt > 0) {
2252 debug_only( int cnt = 0; );
2253 while(major_progress() && (loop_opts_cnt > 0)) {
2254 TracePhase t2("idealLoop", &_t_idealLoop, true);
2255 assert( cnt++ < 40, "infinite cycle in loop optimization" );
2256 PhaseIdealLoop ideal_loop( igvn, true);
2257 loop_opts_cnt--;
2258 if (major_progress()) print_method(PHASE_PHASEIDEALLOOP_ITERATIONS, 2);
2259 if (failing()) return;
2260 }
2261 }
2262
2263 {
2264 // Verify that all previous optimizations produced a valid graph
2265 // at least to this point, even if no loop optimizations were done.
2266 NOT_PRODUCT( TracePhase t2("idealLoopVerify", &_t_idealLoopVerify, TimeCompiler); )
2267 PhaseIdealLoop::verify(igvn);
2268 }
2269
2270 if (range_check_cast_count() > 0) {
2271 // No more loop optimizations. Remove all range check dependent CastIINodes.
2272 C->remove_range_check_casts(igvn);
2273 igvn.optimize();
2274 }
2275
2276 {
2277 NOT_PRODUCT( TracePhase t2("macroExpand", &_t_macroExpand, TimeCompiler); )
2278 PhaseMacroExpand mex(igvn);
2279 if (mex.expand_macro_nodes()) {
2280 assert(failing(), "must bail out w/ explicit message");
2281 return;
2282 }
2283 }
2284
2285 } // (End scope of igvn; run destructor if necessary for asserts.)
2286
2287 dump_inlining();
2288 // A method with only infinite loops has no edges entering loops from root
2289 {
2290 NOT_PRODUCT( TracePhase t2("graphReshape", &_t_graphReshaping, TimeCompiler); )
2291 if (final_graph_reshaping()) {
2292 assert(failing(), "must bail out w/ explicit message");
2293 return;
2294 }
2295 }
2296
2297 print_method(PHASE_OPTIMIZE_FINISHED, 2);
2298 }
2299
2300
2301 //------------------------------Code_Gen---------------------------------------
2302 // Given a graph, generate code for it
2303 void Compile::Code_Gen() {
2304 if (failing()) {
2305 return;
2306 }
2307
2308 // Perform instruction selection. You might think we could reclaim Matcher
2309 // memory PDQ, but actually the Matcher is used in generating spill code.
2310 // Internals of the Matcher (including some VectorSets) must remain live
2311 // for awhile - thus I cannot reclaim Matcher memory lest a VectorSet usage
2312 // set a bit in reclaimed memory.
2313
2314 // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2315 // nodes. Mapping is only valid at the root of each matched subtree.
2316 NOT_PRODUCT( verify_graph_edges(); )
2317
2318 Matcher matcher;
2319 _matcher = &matcher;
2320 {
2321 TracePhase t2("matcher", &_t_matcher, true);
2322 matcher.match();
2323 }
2324 // In debug mode can dump m._nodes.dump() for mapping of ideal to machine
2325 // nodes. Mapping is only valid at the root of each matched subtree.
2326 NOT_PRODUCT( verify_graph_edges(); )
2327
2328 // If you have too many nodes, or if matching has failed, bail out
2329 check_node_count(0, "out of nodes matching instructions");
2330 if (failing()) {
2331 return;
2332 }
2333
2334 // Build a proper-looking CFG
2335 PhaseCFG cfg(node_arena(), root(), matcher);
2336 _cfg = &cfg;
2337 {
2338 NOT_PRODUCT( TracePhase t2("scheduler", &_t_scheduler, TimeCompiler); )
2339 bool success = cfg.do_global_code_motion();
2340 if (!success) {
2341 return;
2342 }
2343
2344 print_method(PHASE_GLOBAL_CODE_MOTION, 2);
2345 NOT_PRODUCT( verify_graph_edges(); )
2346 debug_only( cfg.verify(); )
2347 }
2348
2349 PhaseChaitin regalloc(unique(), cfg, matcher);
2350 _regalloc = ®alloc;
2351 {
2352 TracePhase t2("regalloc", &_t_registerAllocation, true);
2353 // Perform register allocation. After Chaitin, use-def chains are
2354 // no longer accurate (at spill code) and so must be ignored.
2355 // Node->LRG->reg mappings are still accurate.
2356 _regalloc->Register_Allocate();
2357
2358 // Bail out if the allocator builds too many nodes
2359 if (failing()) {
2360 return;
2361 }
2362 }
2363
2364 // Prior to register allocation we kept empty basic blocks in case the
2365 // the allocator needed a place to spill. After register allocation we
2366 // are not adding any new instructions. If any basic block is empty, we
2367 // can now safely remove it.
2368 {
2369 NOT_PRODUCT( TracePhase t2("blockOrdering", &_t_blockOrdering, TimeCompiler); )
2370 cfg.remove_empty_blocks();
2371 if (do_freq_based_layout()) {
2372 PhaseBlockLayout layout(cfg);
2373 } else {
2374 cfg.set_loop_alignment();
2375 }
2376 cfg.fixup_flow();
2377 }
2378
2379 // Apply peephole optimizations
2380 if( OptoPeephole ) {
2381 NOT_PRODUCT( TracePhase t2("peephole", &_t_peephole, TimeCompiler); )
2382 PhasePeephole peep( _regalloc, cfg);
2383 peep.do_transform();
2384 }
2385
2386 // Do late expand if CPU requires this.
2387 if (Matcher::require_postalloc_expand) {
2388 NOT_PRODUCT(TracePhase t2c("postalloc_expand", &_t_postalloc_expand, true));
2389 cfg.postalloc_expand(_regalloc);
2390 }
2391
2392 // Convert Nodes to instruction bits in a buffer
2393 {
2394 // %%%% workspace merge brought two timers together for one job
2395 TracePhase t2a("output", &_t_output, true);
2396 NOT_PRODUCT( TraceTime t2b(NULL, &_t_codeGeneration, TimeCompiler, false); )
2397 Output();
2398 }
2399
2400 print_method(PHASE_FINAL_CODE);
2401
2402 // He's dead, Jim.
2403 _cfg = (PhaseCFG*)((intptr_t)0xdeadbeef);
2404 _regalloc = (PhaseChaitin*)((intptr_t)0xdeadbeef);
2405 }
2406
2407
2408 //------------------------------dump_asm---------------------------------------
2409 // Dump formatted assembly
2410 #ifndef PRODUCT
2411 void Compile::dump_asm(int *pcs, uint pc_limit) {
2412 bool cut_short = false;
2413 tty->print_cr("#");
2414 tty->print("# "); _tf->dump(); tty->cr();
2415 tty->print_cr("#");
2416
2417 // For all blocks
2418 int pc = 0x0; // Program counter
2419 char starts_bundle = ' ';
2420 _regalloc->dump_frame();
2421
2422 Node *n = NULL;
2423 for (uint i = 0; i < _cfg->number_of_blocks(); i++) {
2424 if (VMThread::should_terminate()) {
2425 cut_short = true;
2426 break;
2427 }
2428 Block* block = _cfg->get_block(i);
2429 if (block->is_connector() && !Verbose) {
2430 continue;
2431 }
2432 n = block->head();
2433 if (pcs && n->_idx < pc_limit) {
2434 tty->print("%3.3x ", pcs[n->_idx]);
2435 } else {
2436 tty->print(" ");
2437 }
2438 block->dump_head(_cfg);
2439 if (block->is_connector()) {
2440 tty->print_cr(" # Empty connector block");
2441 } else if (block->num_preds() == 2 && block->pred(1)->is_CatchProj() && block->pred(1)->as_CatchProj()->_con == CatchProjNode::fall_through_index) {
2442 tty->print_cr(" # Block is sole successor of call");
2443 }
2444
2445 // For all instructions
2446 Node *delay = NULL;
2447 for (uint j = 0; j < block->number_of_nodes(); j++) {
2448 if (VMThread::should_terminate()) {
2449 cut_short = true;
2450 break;
2451 }
2452 n = block->get_node(j);
2453 if (valid_bundle_info(n)) {
2454 Bundle* bundle = node_bundling(n);
2455 if (bundle->used_in_unconditional_delay()) {
2456 delay = n;
2457 continue;
2458 }
2459 if (bundle->starts_bundle()) {
2460 starts_bundle = '+';
2461 }
2462 }
2463
2464 if (WizardMode) {
2465 n->dump();
2466 }
2467
2468 if( !n->is_Region() && // Dont print in the Assembly
2469 !n->is_Phi() && // a few noisely useless nodes
2470 !n->is_Proj() &&
2471 !n->is_MachTemp() &&
2472 !n->is_SafePointScalarObject() &&
2473 !n->is_Catch() && // Would be nice to print exception table targets
2474 !n->is_MergeMem() && // Not very interesting
2475 !n->is_top() && // Debug info table constants
2476 !(n->is_Con() && !n->is_Mach())// Debug info table constants
2477 ) {
2478 if (pcs && n->_idx < pc_limit)
2479 tty->print("%3.3x", pcs[n->_idx]);
2480 else
2481 tty->print(" ");
2482 tty->print(" %c ", starts_bundle);
2483 starts_bundle = ' ';
2484 tty->print("\t");
2485 n->format(_regalloc, tty);
2486 tty->cr();
2487 }
2488
2489 // If we have an instruction with a delay slot, and have seen a delay,
2490 // then back up and print it
2491 if (valid_bundle_info(n) && node_bundling(n)->use_unconditional_delay()) {
2492 assert(delay != NULL, "no unconditional delay instruction");
2493 if (WizardMode) delay->dump();
2494
2495 if (node_bundling(delay)->starts_bundle())
2496 starts_bundle = '+';
2497 if (pcs && n->_idx < pc_limit)
2498 tty->print("%3.3x", pcs[n->_idx]);
2499 else
2500 tty->print(" ");
2501 tty->print(" %c ", starts_bundle);
2502 starts_bundle = ' ';
2503 tty->print("\t");
2504 delay->format(_regalloc, tty);
2505 tty->cr();
2506 delay = NULL;
2507 }
2508
2509 // Dump the exception table as well
2510 if( n->is_Catch() && (Verbose || WizardMode) ) {
2511 // Print the exception table for this offset
2512 _handler_table.print_subtable_for(pc);
2513 }
2514 }
2515
2516 if (pcs && n->_idx < pc_limit)
2517 tty->print_cr("%3.3x", pcs[n->_idx]);
2518 else
2519 tty->cr();
2520
2521 assert(cut_short || delay == NULL, "no unconditional delay branch");
2522
2523 } // End of per-block dump
2524 tty->cr();
2525
2526 if (cut_short) tty->print_cr("*** disassembly is cut short ***");
2527 }
2528 #endif
2529
2530 //------------------------------Final_Reshape_Counts---------------------------
2531 // This class defines counters to help identify when a method
2532 // may/must be executed using hardware with only 24-bit precision.
2533 struct Final_Reshape_Counts : public StackObj {
2534 int _call_count; // count non-inlined 'common' calls
2535 int _float_count; // count float ops requiring 24-bit precision
2536 int _double_count; // count double ops requiring more precision
2537 int _java_call_count; // count non-inlined 'java' calls
2538 int _inner_loop_count; // count loops which need alignment
2539 VectorSet _visited; // Visitation flags
2540 Node_List _tests; // Set of IfNodes & PCTableNodes
2541
2542 Final_Reshape_Counts() :
2543 _call_count(0), _float_count(0), _double_count(0),
2544 _java_call_count(0), _inner_loop_count(0),
2545 _visited( Thread::current()->resource_area() ) { }
2546
2547 void inc_call_count () { _call_count ++; }
2548 void inc_float_count () { _float_count ++; }
2549 void inc_double_count() { _double_count++; }
2550 void inc_java_call_count() { _java_call_count++; }
2551 void inc_inner_loop_count() { _inner_loop_count++; }
2552
2553 int get_call_count () const { return _call_count ; }
2554 int get_float_count () const { return _float_count ; }
2555 int get_double_count() const { return _double_count; }
2556 int get_java_call_count() const { return _java_call_count; }
2557 int get_inner_loop_count() const { return _inner_loop_count; }
2558 };
2559
2560 #ifdef ASSERT
2561 static bool oop_offset_is_sane(const TypeInstPtr* tp) {
2562 ciInstanceKlass *k = tp->klass()->as_instance_klass();
2563 // Make sure the offset goes inside the instance layout.
2564 return k->contains_field_offset(tp->offset());
2565 // Note that OffsetBot and OffsetTop are very negative.
2566 }
2567 #endif
2568
2569 // Eliminate trivially redundant StoreCMs and accumulate their
2570 // precedence edges.
2571 void Compile::eliminate_redundant_card_marks(Node* n) {
2572 assert(n->Opcode() == Op_StoreCM, "expected StoreCM");
2573 if (n->in(MemNode::Address)->outcnt() > 1) {
2574 // There are multiple users of the same address so it might be
2575 // possible to eliminate some of the StoreCMs
2576 Node* mem = n->in(MemNode::Memory);
2577 Node* adr = n->in(MemNode::Address);
2578 Node* val = n->in(MemNode::ValueIn);
2579 Node* prev = n;
2580 bool done = false;
2581 // Walk the chain of StoreCMs eliminating ones that match. As
2582 // long as it's a chain of single users then the optimization is
2583 // safe. Eliminating partially redundant StoreCMs would require
2584 // cloning copies down the other paths.
2585 while (mem->Opcode() == Op_StoreCM && mem->outcnt() == 1 && !done) {
2586 if (adr == mem->in(MemNode::Address) &&
2587 val == mem->in(MemNode::ValueIn)) {
2588 // redundant StoreCM
2589 if (mem->req() > MemNode::OopStore) {
2590 // Hasn't been processed by this code yet.
2591 n->add_prec(mem->in(MemNode::OopStore));
2592 } else {
2593 // Already converted to precedence edge
2594 for (uint i = mem->req(); i < mem->len(); i++) {
2595 // Accumulate any precedence edges
2596 if (mem->in(i) != NULL) {
2597 n->add_prec(mem->in(i));
2598 }
2599 }
2600 // Everything above this point has been processed.
2601 done = true;
2602 }
2603 // Eliminate the previous StoreCM
2604 prev->set_req(MemNode::Memory, mem->in(MemNode::Memory));
2605 assert(mem->outcnt() == 0, "should be dead");
2606 mem->disconnect_inputs(NULL, this);
2607 } else {
2608 prev = mem;
2609 }
2610 mem = prev->in(MemNode::Memory);
2611 }
2612 }
2613 }
2614
2615 //------------------------------final_graph_reshaping_impl----------------------
2616 // Implement items 1-5 from final_graph_reshaping below.
2617 void Compile::final_graph_reshaping_impl( Node *n, Final_Reshape_Counts &frc) {
2618
2619 if ( n->outcnt() == 0 ) return; // dead node
2620 uint nop = n->Opcode();
2621
2622 // Check for 2-input instruction with "last use" on right input.
2623 // Swap to left input. Implements item (2).
2624 if( n->req() == 3 && // two-input instruction
2625 n->in(1)->outcnt() > 1 && // left use is NOT a last use
2626 (!n->in(1)->is_Phi() || n->in(1)->in(2) != n) && // it is not data loop
2627 n->in(2)->outcnt() == 1 &&// right use IS a last use
2628 !n->in(2)->is_Con() ) { // right use is not a constant
2629 // Check for commutative opcode
2630 switch( nop ) {
2631 case Op_AddI: case Op_AddF: case Op_AddD: case Op_AddL:
2632 case Op_MaxI: case Op_MinI:
2633 case Op_MulI: case Op_MulF: case Op_MulD: case Op_MulL:
2634 case Op_AndL: case Op_XorL: case Op_OrL:
2635 case Op_AndI: case Op_XorI: case Op_OrI: {
2636 // Move "last use" input to left by swapping inputs
2637 n->swap_edges(1, 2);
2638 break;
2639 }
2640 default:
2641 break;
2642 }
2643 }
2644
2645 #ifdef ASSERT
2646 if( n->is_Mem() ) {
2647 int alias_idx = get_alias_index(n->as_Mem()->adr_type());
2648 assert( n->in(0) != NULL || alias_idx != Compile::AliasIdxRaw ||
2649 // oop will be recorded in oop map if load crosses safepoint
2650 n->is_Load() && (n->as_Load()->bottom_type()->isa_oopptr() ||
2651 LoadNode::is_immutable_value(n->in(MemNode::Address))),
2652 "raw memory operations should have control edge");
2653 }
2654 #endif
2655 // Count FPU ops and common calls, implements item (3)
2656 switch( nop ) {
2657 // Count all float operations that may use FPU
2658 case Op_AddF:
2659 case Op_SubF:
2660 case Op_MulF:
2661 case Op_DivF:
2662 case Op_NegF:
2663 case Op_ModF:
2664 case Op_ConvI2F:
2665 case Op_ConF:
2666 case Op_CmpF:
2667 case Op_CmpF3:
2668 // case Op_ConvL2F: // longs are split into 32-bit halves
2669 frc.inc_float_count();
2670 break;
2671
2672 case Op_ConvF2D:
2673 case Op_ConvD2F:
2674 frc.inc_float_count();
2675 frc.inc_double_count();
2676 break;
2677
2678 // Count all double operations that may use FPU
2679 case Op_AddD:
2680 case Op_SubD:
2681 case Op_MulD:
2682 case Op_DivD:
2683 case Op_NegD:
2684 case Op_ModD:
2685 case Op_ConvI2D:
2686 case Op_ConvD2I:
2687 // case Op_ConvL2D: // handled by leaf call
2688 // case Op_ConvD2L: // handled by leaf call
2689 case Op_ConD:
2690 case Op_CmpD:
2691 case Op_CmpD3:
2692 frc.inc_double_count();
2693 break;
2694 case Op_Opaque1: // Remove Opaque Nodes before matching
2695 case Op_Opaque2: // Remove Opaque Nodes before matching
2696 case Op_Opaque3:
2697 n->subsume_by(n->in(1), this);
2698 break;
2699 case Op_CallStaticJava:
2700 case Op_CallJava:
2701 case Op_CallDynamicJava:
2702 frc.inc_java_call_count(); // Count java call site;
2703 case Op_CallRuntime:
2704 case Op_CallLeaf:
2705 case Op_CallLeafNoFP: {
2706 assert( n->is_Call(), "" );
2707 CallNode *call = n->as_Call();
2708 // Count call sites where the FP mode bit would have to be flipped.
2709 // Do not count uncommon runtime calls:
2710 // uncommon_trap, _complete_monitor_locking, _complete_monitor_unlocking,
2711 // _new_Java, _new_typeArray, _new_objArray, _rethrow_Java, ...
2712 if( !call->is_CallStaticJava() || !call->as_CallStaticJava()->_name ) {
2713 frc.inc_call_count(); // Count the call site
2714 } else { // See if uncommon argument is shared
2715 Node *n = call->in(TypeFunc::Parms);
2716 int nop = n->Opcode();
2717 // Clone shared simple arguments to uncommon calls, item (1).
2718 if( n->outcnt() > 1 &&
2719 !n->is_Proj() &&
2720 nop != Op_CreateEx &&
2721 nop != Op_CheckCastPP &&
2722 nop != Op_DecodeN &&
2723 nop != Op_DecodeNKlass &&
2724 !n->is_Mem() ) {
2725 Node *x = n->clone();
2726 call->set_req( TypeFunc::Parms, x );
2727 }
2728 }
2729 break;
2730 }
2731
2732 case Op_StoreD:
2733 case Op_LoadD:
2734 case Op_LoadD_unaligned:
2735 frc.inc_double_count();
2736 goto handle_mem;
2737 case Op_StoreF:
2738 case Op_LoadF:
2739 frc.inc_float_count();
2740 goto handle_mem;
2741
2742 case Op_StoreCM:
2743 {
2744 // Convert OopStore dependence into precedence edge
2745 Node* prec = n->in(MemNode::OopStore);
2746 n->del_req(MemNode::OopStore);
2747 n->add_prec(prec);
2748 eliminate_redundant_card_marks(n);
2749 }
2750
2751 // fall through
2752
2753 case Op_StoreB:
2754 case Op_StoreC:
2755 case Op_StorePConditional:
2756 case Op_StoreI:
2757 case Op_StoreL:
2758 case Op_StoreIConditional:
2759 case Op_StoreLConditional:
2760 case Op_CompareAndSwapI:
2761 case Op_CompareAndSwapL:
2762 case Op_CompareAndSwapP:
2763 case Op_CompareAndSwapN:
2764 case Op_GetAndAddI:
2765 case Op_GetAndAddL:
2766 case Op_GetAndSetI:
2767 case Op_GetAndSetL:
2768 case Op_GetAndSetP:
2769 case Op_GetAndSetN:
2770 case Op_StoreP:
2771 case Op_StoreN:
2772 case Op_StoreNKlass:
2773 case Op_LoadB:
2774 case Op_LoadUB:
2775 case Op_LoadUS:
2776 case Op_LoadI:
2777 case Op_LoadKlass:
2778 case Op_LoadNKlass:
2779 case Op_LoadL:
2780 case Op_LoadL_unaligned:
2781 case Op_LoadPLocked:
2782 case Op_LoadP:
2783 case Op_LoadN:
2784 case Op_LoadRange:
2785 case Op_LoadS: {
2786 handle_mem:
2787 #ifdef ASSERT
2788 if( VerifyOptoOopOffsets ) {
2789 assert( n->is_Mem(), "" );
2790 MemNode *mem = (MemNode*)n;
2791 // Check to see if address types have grounded out somehow.
2792 const TypeInstPtr *tp = mem->in(MemNode::Address)->bottom_type()->isa_instptr();
2793 assert( !tp || oop_offset_is_sane(tp), "" );
2794 }
2795 #endif
2796 break;
2797 }
2798
2799 case Op_AddP: { // Assert sane base pointers
2800 Node *addp = n->in(AddPNode::Address);
2801 assert( !addp->is_AddP() ||
2802 addp->in(AddPNode::Base)->is_top() || // Top OK for allocation
2803 addp->in(AddPNode::Base) == n->in(AddPNode::Base),
2804 "Base pointers must match" );
2805 #ifdef _LP64
2806 if ((UseCompressedOops || UseCompressedClassPointers) &&
2807 addp->Opcode() == Op_ConP &&
2808 addp == n->in(AddPNode::Base) &&
2809 n->in(AddPNode::Offset)->is_Con()) {
2810 // Use addressing with narrow klass to load with offset on x86.
2811 // On sparc loading 32-bits constant and decoding it have less
2812 // instructions (4) then load 64-bits constant (7).
2813 // Do this transformation here since IGVN will convert ConN back to ConP.
2814 const Type* t = addp->bottom_type();
2815 if (t->isa_oopptr() || t->isa_klassptr()) {
2816 Node* nn = NULL;
2817
2818 int op = t->isa_oopptr() ? Op_ConN : Op_ConNKlass;
2819
2820 // Look for existing ConN node of the same exact type.
2821 Node* r = root();
2822 uint cnt = r->outcnt();
2823 for (uint i = 0; i < cnt; i++) {
2824 Node* m = r->raw_out(i);
2825 if (m!= NULL && m->Opcode() == op &&
2826 m->bottom_type()->make_ptr() == t) {
2827 nn = m;
2828 break;
2829 }
2830 }
2831 if (nn != NULL) {
2832 // Decode a narrow oop to match address
2833 // [R12 + narrow_oop_reg<<3 + offset]
2834 if (t->isa_oopptr()) {
2835 nn = new (this) DecodeNNode(nn, t);
2836 } else {
2837 nn = new (this) DecodeNKlassNode(nn, t);
2838 }
2839 n->set_req(AddPNode::Base, nn);
2840 n->set_req(AddPNode::Address, nn);
2841 if (addp->outcnt() == 0) {
2842 addp->disconnect_inputs(NULL, this);
2843 }
2844 }
2845 }
2846 }
2847 #endif
2848 break;
2849 }
2850
2851 #ifdef _LP64
2852 case Op_CastPP:
2853 if (n->in(1)->is_DecodeN() && Matcher::gen_narrow_oop_implicit_null_checks()) {
2854 Node* in1 = n->in(1);
2855 const Type* t = n->bottom_type();
2856 Node* new_in1 = in1->clone();
2857 new_in1->as_DecodeN()->set_type(t);
2858
2859 if (!Matcher::narrow_oop_use_complex_address()) {
2860 //
2861 // x86, ARM and friends can handle 2 adds in addressing mode
2862 // and Matcher can fold a DecodeN node into address by using
2863 // a narrow oop directly and do implicit NULL check in address:
2864 //
2865 // [R12 + narrow_oop_reg<<3 + offset]
2866 // NullCheck narrow_oop_reg
2867 //
2868 // On other platforms (Sparc) we have to keep new DecodeN node and
2869 // use it to do implicit NULL check in address:
2870 //
2871 // decode_not_null narrow_oop_reg, base_reg
2872 // [base_reg + offset]
2873 // NullCheck base_reg
2874 //
2875 // Pin the new DecodeN node to non-null path on these platform (Sparc)
2876 // to keep the information to which NULL check the new DecodeN node
2877 // corresponds to use it as value in implicit_null_check().
2878 //
2879 new_in1->set_req(0, n->in(0));
2880 }
2881
2882 n->subsume_by(new_in1, this);
2883 if (in1->outcnt() == 0) {
2884 in1->disconnect_inputs(NULL, this);
2885 }
2886 }
2887 break;
2888
2889 case Op_CmpP:
2890 // Do this transformation here to preserve CmpPNode::sub() and
2891 // other TypePtr related Ideal optimizations (for example, ptr nullness).
2892 if (n->in(1)->is_DecodeNarrowPtr() || n->in(2)->is_DecodeNarrowPtr()) {
2893 Node* in1 = n->in(1);
2894 Node* in2 = n->in(2);
2895 if (!in1->is_DecodeNarrowPtr()) {
2896 in2 = in1;
2897 in1 = n->in(2);
2898 }
2899 assert(in1->is_DecodeNarrowPtr(), "sanity");
2900
2901 Node* new_in2 = NULL;
2902 if (in2->is_DecodeNarrowPtr()) {
2903 assert(in2->Opcode() == in1->Opcode(), "must be same node type");
2904 new_in2 = in2->in(1);
2905 } else if (in2->Opcode() == Op_ConP) {
2906 const Type* t = in2->bottom_type();
2907 if (t == TypePtr::NULL_PTR) {
2908 assert(in1->is_DecodeN(), "compare klass to null?");
2909 // Don't convert CmpP null check into CmpN if compressed
2910 // oops implicit null check is not generated.
2911 // This will allow to generate normal oop implicit null check.
2912 if (Matcher::gen_narrow_oop_implicit_null_checks())
2913 new_in2 = ConNode::make(this, TypeNarrowOop::NULL_PTR);
2914 //
2915 // This transformation together with CastPP transformation above
2916 // will generated code for implicit NULL checks for compressed oops.
2917 //
2918 // The original code after Optimize()
2919 //
2920 // LoadN memory, narrow_oop_reg
2921 // decode narrow_oop_reg, base_reg
2922 // CmpP base_reg, NULL
2923 // CastPP base_reg // NotNull
2924 // Load [base_reg + offset], val_reg
2925 //
2926 // after these transformations will be
2927 //
2928 // LoadN memory, narrow_oop_reg
2929 // CmpN narrow_oop_reg, NULL
2930 // decode_not_null narrow_oop_reg, base_reg
2931 // Load [base_reg + offset], val_reg
2932 //
2933 // and the uncommon path (== NULL) will use narrow_oop_reg directly
2934 // since narrow oops can be used in debug info now (see the code in
2935 // final_graph_reshaping_walk()).
2936 //
2937 // At the end the code will be matched to
2938 // on x86:
2939 //
2940 // Load_narrow_oop memory, narrow_oop_reg
2941 // Load [R12 + narrow_oop_reg<<3 + offset], val_reg
2942 // NullCheck narrow_oop_reg
2943 //
2944 // and on sparc:
2945 //
2946 // Load_narrow_oop memory, narrow_oop_reg
2947 // decode_not_null narrow_oop_reg, base_reg
2948 // Load [base_reg + offset], val_reg
2949 // NullCheck base_reg
2950 //
2951 } else if (t->isa_oopptr()) {
2952 new_in2 = ConNode::make(this, t->make_narrowoop());
2953 } else if (t->isa_klassptr()) {
2954 new_in2 = ConNode::make(this, t->make_narrowklass());
2955 }
2956 }
2957 if (new_in2 != NULL) {
2958 Node* cmpN = new (this) CmpNNode(in1->in(1), new_in2);
2959 n->subsume_by(cmpN, this);
2960 if (in1->outcnt() == 0) {
2961 in1->disconnect_inputs(NULL, this);
2962 }
2963 if (in2->outcnt() == 0) {
2964 in2->disconnect_inputs(NULL, this);
2965 }
2966 }
2967 }
2968 break;
2969
2970 case Op_DecodeN:
2971 case Op_DecodeNKlass:
2972 assert(!n->in(1)->is_EncodeNarrowPtr(), "should be optimized out");
2973 // DecodeN could be pinned when it can't be fold into
2974 // an address expression, see the code for Op_CastPP above.
2975 assert(n->in(0) == NULL || (UseCompressedOops && !Matcher::narrow_oop_use_complex_address()), "no control");
2976 break;
2977
2978 case Op_EncodeP:
2979 case Op_EncodePKlass: {
2980 Node* in1 = n->in(1);
2981 if (in1->is_DecodeNarrowPtr()) {
2982 n->subsume_by(in1->in(1), this);
2983 } else if (in1->Opcode() == Op_ConP) {
2984 const Type* t = in1->bottom_type();
2985 if (t == TypePtr::NULL_PTR) {
2986 assert(t->isa_oopptr(), "null klass?");
2987 n->subsume_by(ConNode::make(this, TypeNarrowOop::NULL_PTR), this);
2988 } else if (t->isa_oopptr()) {
2989 n->subsume_by(ConNode::make(this, t->make_narrowoop()), this);
2990 } else if (t->isa_klassptr()) {
2991 n->subsume_by(ConNode::make(this, t->make_narrowklass()), this);
2992 }
2993 }
2994 if (in1->outcnt() == 0) {
2995 in1->disconnect_inputs(NULL, this);
2996 }
2997 break;
2998 }
2999
3000 case Op_Proj: {
3001 if (OptimizeStringConcat) {
3002 ProjNode* p = n->as_Proj();
3003 if (p->_is_io_use) {
3004 // Separate projections were used for the exception path which
3005 // are normally removed by a late inline. If it wasn't inlined
3006 // then they will hang around and should just be replaced with
3007 // the original one.
3008 Node* proj = NULL;
3009 // Replace with just one
3010 for (SimpleDUIterator i(p->in(0)); i.has_next(); i.next()) {
3011 Node *use = i.get();
3012 if (use->is_Proj() && p != use && use->as_Proj()->_con == p->_con) {
3013 proj = use;
3014 break;
3015 }
3016 }
3017 assert(proj != NULL, "must be found");
3018 p->subsume_by(proj, this);
3019 }
3020 }
3021 break;
3022 }
3023
3024 case Op_Phi:
3025 if (n->as_Phi()->bottom_type()->isa_narrowoop() || n->as_Phi()->bottom_type()->isa_narrowklass()) {
3026 // The EncodeP optimization may create Phi with the same edges
3027 // for all paths. It is not handled well by Register Allocator.
3028 Node* unique_in = n->in(1);
3029 assert(unique_in != NULL, "");
3030 uint cnt = n->req();
3031 for (uint i = 2; i < cnt; i++) {
3032 Node* m = n->in(i);
3033 assert(m != NULL, "");
3034 if (unique_in != m)
3035 unique_in = NULL;
3036 }
3037 if (unique_in != NULL) {
3038 n->subsume_by(unique_in, this);
3039 }
3040 }
3041 break;
3042
3043 #endif
3044
3045 #ifdef ASSERT
3046 case Op_CastII:
3047 // Verify that all range check dependent CastII nodes were removed.
3048 if (n->isa_CastII()->has_range_check()) {
3049 n->dump(3);
3050 assert(false, "Range check dependent CastII node was not removed");
3051 }
3052 break;
3053 #endif
3054
3055 case Op_ModI:
3056 if (UseDivMod) {
3057 // Check if a%b and a/b both exist
3058 Node* d = n->find_similar(Op_DivI);
3059 if (d) {
3060 // Replace them with a fused divmod if supported
3061 if (Matcher::has_match_rule(Op_DivModI)) {
3062 DivModINode* divmod = DivModINode::make(this, n);
3063 d->subsume_by(divmod->div_proj(), this);
3064 n->subsume_by(divmod->mod_proj(), this);
3065 } else {
3066 // replace a%b with a-((a/b)*b)
3067 Node* mult = new (this) MulINode(d, d->in(2));
3068 Node* sub = new (this) SubINode(d->in(1), mult);
3069 n->subsume_by(sub, this);
3070 }
3071 }
3072 }
3073 break;
3074
3075 case Op_ModL:
3076 if (UseDivMod) {
3077 // Check if a%b and a/b both exist
3078 Node* d = n->find_similar(Op_DivL);
3079 if (d) {
3080 // Replace them with a fused divmod if supported
3081 if (Matcher::has_match_rule(Op_DivModL)) {
3082 DivModLNode* divmod = DivModLNode::make(this, n);
3083 d->subsume_by(divmod->div_proj(), this);
3084 n->subsume_by(divmod->mod_proj(), this);
3085 } else {
3086 // replace a%b with a-((a/b)*b)
3087 Node* mult = new (this) MulLNode(d, d->in(2));
3088 Node* sub = new (this) SubLNode(d->in(1), mult);
3089 n->subsume_by(sub, this);
3090 }
3091 }
3092 }
3093 break;
3094
3095 case Op_LoadVector:
3096 case Op_StoreVector:
3097 break;
3098
3099 case Op_PackB:
3100 case Op_PackS:
3101 case Op_PackI:
3102 case Op_PackF:
3103 case Op_PackL:
3104 case Op_PackD:
3105 if (n->req()-1 > 2) {
3106 // Replace many operand PackNodes with a binary tree for matching
3107 PackNode* p = (PackNode*) n;
3108 Node* btp = p->binary_tree_pack(this, 1, n->req());
3109 n->subsume_by(btp, this);
3110 }
3111 break;
3112 case Op_Loop:
3113 case Op_CountedLoop:
3114 if (n->as_Loop()->is_inner_loop()) {
3115 frc.inc_inner_loop_count();
3116 }
3117 break;
3118 case Op_LShiftI:
3119 case Op_RShiftI:
3120 case Op_URShiftI:
3121 case Op_LShiftL:
3122 case Op_RShiftL:
3123 case Op_URShiftL:
3124 if (Matcher::need_masked_shift_count) {
3125 // The cpu's shift instructions don't restrict the count to the
3126 // lower 5/6 bits. We need to do the masking ourselves.
3127 Node* in2 = n->in(2);
3128 juint mask = (n->bottom_type() == TypeInt::INT) ? (BitsPerInt - 1) : (BitsPerLong - 1);
3129 const TypeInt* t = in2->find_int_type();
3130 if (t != NULL && t->is_con()) {
3131 juint shift = t->get_con();
3132 if (shift > mask) { // Unsigned cmp
3133 n->set_req(2, ConNode::make(this, TypeInt::make(shift & mask)));
3134 }
3135 } else {
3136 if (t == NULL || t->_lo < 0 || t->_hi > (int)mask) {
3137 Node* shift = new (this) AndINode(in2, ConNode::make(this, TypeInt::make(mask)));
3138 n->set_req(2, shift);
3139 }
3140 }
3141 if (in2->outcnt() == 0) { // Remove dead node
3142 in2->disconnect_inputs(NULL, this);
3143 }
3144 }
3145 break;
3146 case Op_MemBarStoreStore:
3147 case Op_MemBarRelease:
3148 // Break the link with AllocateNode: it is no longer useful and
3149 // confuses register allocation.
3150 if (n->req() > MemBarNode::Precedent) {
3151 n->set_req(MemBarNode::Precedent, top());
3152 }
3153 break;
3154 default:
3155 assert( !n->is_Call(), "" );
3156 assert( !n->is_Mem(), "" );
3157 assert( nop != Op_ProfileBoolean, "should be eliminated during IGVN");
3158 break;
3159 }
3160
3161 // Collect CFG split points
3162 if (n->is_MultiBranch())
3163 frc._tests.push(n);
3164 }
3165
3166 //------------------------------final_graph_reshaping_walk---------------------
3167 // Replacing Opaque nodes with their input in final_graph_reshaping_impl(),
3168 // requires that the walk visits a node's inputs before visiting the node.
3169 void Compile::final_graph_reshaping_walk( Node_Stack &nstack, Node *root, Final_Reshape_Counts &frc ) {
3170 ResourceArea *area = Thread::current()->resource_area();
3171 Unique_Node_List sfpt(area);
3172
3173 frc._visited.set(root->_idx); // first, mark node as visited
3174 uint cnt = root->req();
3175 Node *n = root;
3176 uint i = 0;
3177 while (true) {
3178 if (i < cnt) {
3179 // Place all non-visited non-null inputs onto stack
3180 Node* m = n->in(i);
3181 ++i;
3182 if (m != NULL && !frc._visited.test_set(m->_idx)) {
3183 if (m->is_SafePoint() && m->as_SafePoint()->jvms() != NULL) {
3184 // compute worst case interpreter size in case of a deoptimization
3185 update_interpreter_frame_size(m->as_SafePoint()->jvms()->interpreter_frame_size());
3186
3187 sfpt.push(m);
3188 }
3189 cnt = m->req();
3190 nstack.push(n, i); // put on stack parent and next input's index
3191 n = m;
3192 i = 0;
3193 }
3194 } else {
3195 // Now do post-visit work
3196 final_graph_reshaping_impl( n, frc );
3197 if (nstack.is_empty())
3198 break; // finished
3199 n = nstack.node(); // Get node from stack
3200 cnt = n->req();
3201 i = nstack.index();
3202 nstack.pop(); // Shift to the next node on stack
3203 }
3204 }
3205
3206 // Skip next transformation if compressed oops are not used.
3207 if ((UseCompressedOops && !Matcher::gen_narrow_oop_implicit_null_checks()) ||
3208 (!UseCompressedOops && !UseCompressedClassPointers))
3209 return;
3210
3211 // Go over safepoints nodes to skip DecodeN/DecodeNKlass nodes for debug edges.
3212 // It could be done for an uncommon traps or any safepoints/calls
3213 // if the DecodeN/DecodeNKlass node is referenced only in a debug info.
3214 while (sfpt.size() > 0) {
3215 n = sfpt.pop();
3216 JVMState *jvms = n->as_SafePoint()->jvms();
3217 assert(jvms != NULL, "sanity");
3218 int start = jvms->debug_start();
3219 int end = n->req();
3220 bool is_uncommon = (n->is_CallStaticJava() &&
3221 n->as_CallStaticJava()->uncommon_trap_request() != 0);
3222 for (int j = start; j < end; j++) {
3223 Node* in = n->in(j);
3224 if (in->is_DecodeNarrowPtr()) {
3225 bool safe_to_skip = true;
3226 if (!is_uncommon ) {
3227 // Is it safe to skip?
3228 for (uint i = 0; i < in->outcnt(); i++) {
3229 Node* u = in->raw_out(i);
3230 if (!u->is_SafePoint() ||
3231 u->is_Call() && u->as_Call()->has_non_debug_use(n)) {
3232 safe_to_skip = false;
3233 }
3234 }
3235 }
3236 if (safe_to_skip) {
3237 n->set_req(j, in->in(1));
3238 }
3239 if (in->outcnt() == 0) {
3240 in->disconnect_inputs(NULL, this);
3241 }
3242 }
3243 }
3244 }
3245 }
3246
3247 //------------------------------final_graph_reshaping--------------------------
3248 // Final Graph Reshaping.
3249 //
3250 // (1) Clone simple inputs to uncommon calls, so they can be scheduled late
3251 // and not commoned up and forced early. Must come after regular
3252 // optimizations to avoid GVN undoing the cloning. Clone constant
3253 // inputs to Loop Phis; these will be split by the allocator anyways.
3254 // Remove Opaque nodes.
3255 // (2) Move last-uses by commutative operations to the left input to encourage
3256 // Intel update-in-place two-address operations and better register usage
3257 // on RISCs. Must come after regular optimizations to avoid GVN Ideal
3258 // calls canonicalizing them back.
3259 // (3) Count the number of double-precision FP ops, single-precision FP ops
3260 // and call sites. On Intel, we can get correct rounding either by
3261 // forcing singles to memory (requires extra stores and loads after each
3262 // FP bytecode) or we can set a rounding mode bit (requires setting and
3263 // clearing the mode bit around call sites). The mode bit is only used
3264 // if the relative frequency of single FP ops to calls is low enough.
3265 // This is a key transform for SPEC mpeg_audio.
3266 // (4) Detect infinite loops; blobs of code reachable from above but not
3267 // below. Several of the Code_Gen algorithms fail on such code shapes,
3268 // so we simply bail out. Happens a lot in ZKM.jar, but also happens
3269 // from time to time in other codes (such as -Xcomp finalizer loops, etc).
3270 // Detection is by looking for IfNodes where only 1 projection is
3271 // reachable from below or CatchNodes missing some targets.
3272 // (5) Assert for insane oop offsets in debug mode.
3273
3274 bool Compile::final_graph_reshaping() {
3275 // an infinite loop may have been eliminated by the optimizer,
3276 // in which case the graph will be empty.
3277 if (root()->req() == 1) {
3278 record_method_not_compilable("trivial infinite loop");
3279 return true;
3280 }
3281
3282 // Expensive nodes have their control input set to prevent the GVN
3283 // from freely commoning them. There's no GVN beyond this point so
3284 // no need to keep the control input. We want the expensive nodes to
3285 // be freely moved to the least frequent code path by gcm.
3286 assert(OptimizeExpensiveOps || expensive_count() == 0, "optimization off but list non empty?");
3287 for (int i = 0; i < expensive_count(); i++) {
3288 _expensive_nodes->at(i)->set_req(0, NULL);
3289 }
3290
3291 Final_Reshape_Counts frc;
3292
3293 // Visit everybody reachable!
3294 // Allocate stack of size C->live_nodes()/2 to avoid frequent realloc
3295 Node_Stack nstack(live_nodes() >> 1);
3296 final_graph_reshaping_walk(nstack, root(), frc);
3297
3298 // Check for unreachable (from below) code (i.e., infinite loops).
3299 for( uint i = 0; i < frc._tests.size(); i++ ) {
3300 MultiBranchNode *n = frc._tests[i]->as_MultiBranch();
3301 // Get number of CFG targets.
3302 // Note that PCTables include exception targets after calls.
3303 uint required_outcnt = n->required_outcnt();
3304 if (n->outcnt() != required_outcnt) {
3305 // Check for a few special cases. Rethrow Nodes never take the
3306 // 'fall-thru' path, so expected kids is 1 less.
3307 if (n->is_PCTable() && n->in(0) && n->in(0)->in(0)) {
3308 if (n->in(0)->in(0)->is_Call()) {
3309 CallNode *call = n->in(0)->in(0)->as_Call();
3310 if (call->entry_point() == OptoRuntime::rethrow_stub()) {
3311 required_outcnt--; // Rethrow always has 1 less kid
3312 } else if (call->req() > TypeFunc::Parms &&
3313 call->is_CallDynamicJava()) {
3314 // Check for null receiver. In such case, the optimizer has
3315 // detected that the virtual call will always result in a null
3316 // pointer exception. The fall-through projection of this CatchNode
3317 // will not be populated.
3318 Node *arg0 = call->in(TypeFunc::Parms);
3319 if (arg0->is_Type() &&
3320 arg0->as_Type()->type()->higher_equal(TypePtr::NULL_PTR)) {
3321 required_outcnt--;
3322 }
3323 } else if (call->entry_point() == OptoRuntime::new_array_Java() &&
3324 call->req() > TypeFunc::Parms+1 &&
3325 call->is_CallStaticJava()) {
3326 // Check for negative array length. In such case, the optimizer has
3327 // detected that the allocation attempt will always result in an
3328 // exception. There is no fall-through projection of this CatchNode .
3329 Node *arg1 = call->in(TypeFunc::Parms+1);
3330 if (arg1->is_Type() &&
3331 arg1->as_Type()->type()->join(TypeInt::POS)->empty()) {
3332 required_outcnt--;
3333 }
3334 }
3335 }
3336 }
3337 // Recheck with a better notion of 'required_outcnt'
3338 if (n->outcnt() != required_outcnt) {
3339 record_method_not_compilable("malformed control flow");
3340 return true; // Not all targets reachable!
3341 }
3342 }
3343 // Check that I actually visited all kids. Unreached kids
3344 // must be infinite loops.
3345 for (DUIterator_Fast jmax, j = n->fast_outs(jmax); j < jmax; j++)
3346 if (!frc._visited.test(n->fast_out(j)->_idx)) {
3347 record_method_not_compilable("infinite loop");
3348 return true; // Found unvisited kid; must be unreach
3349 }
3350 }
3351
3352 // If original bytecodes contained a mixture of floats and doubles
3353 // check if the optimizer has made it homogenous, item (3).
3354 if( Use24BitFPMode && Use24BitFP && UseSSE == 0 &&
3355 frc.get_float_count() > 32 &&
3356 frc.get_double_count() == 0 &&
3357 (10 * frc.get_call_count() < frc.get_float_count()) ) {
3358 set_24_bit_selection_and_mode( false, true );
3359 }
3360
3361 set_java_calls(frc.get_java_call_count());
3362 set_inner_loops(frc.get_inner_loop_count());
3363
3364 // No infinite loops, no reason to bail out.
3365 return false;
3366 }
3367
3368 //-----------------------------too_many_traps----------------------------------
3369 // Report if there are too many traps at the current method and bci.
3370 // Return true if there was a trap, and/or PerMethodTrapLimit is exceeded.
3371 bool Compile::too_many_traps(ciMethod* method,
3372 int bci,
3373 Deoptimization::DeoptReason reason) {
3374 ciMethodData* md = method->method_data();
3375 if (md->is_empty()) {
3376 // Assume the trap has not occurred, or that it occurred only
3377 // because of a transient condition during start-up in the interpreter.
3378 return false;
3379 }
3380 ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3381 if (md->has_trap_at(bci, m, reason) != 0) {
3382 // Assume PerBytecodeTrapLimit==0, for a more conservative heuristic.
3383 // Also, if there are multiple reasons, or if there is no per-BCI record,
3384 // assume the worst.
3385 if (log())
3386 log()->elem("observe trap='%s' count='%d'",
3387 Deoptimization::trap_reason_name(reason),
3388 md->trap_count(reason));
3389 return true;
3390 } else {
3391 // Ignore method/bci and see if there have been too many globally.
3392 return too_many_traps(reason, md);
3393 }
3394 }
3395
3396 // Less-accurate variant which does not require a method and bci.
3397 bool Compile::too_many_traps(Deoptimization::DeoptReason reason,
3398 ciMethodData* logmd) {
3399 if (trap_count(reason) >= Deoptimization::per_method_trap_limit(reason)) {
3400 // Too many traps globally.
3401 // Note that we use cumulative trap_count, not just md->trap_count.
3402 if (log()) {
3403 int mcount = (logmd == NULL)? -1: (int)logmd->trap_count(reason);
3404 log()->elem("observe trap='%s' count='0' mcount='%d' ccount='%d'",
3405 Deoptimization::trap_reason_name(reason),
3406 mcount, trap_count(reason));
3407 }
3408 return true;
3409 } else {
3410 // The coast is clear.
3411 return false;
3412 }
3413 }
3414
3415 //--------------------------too_many_recompiles--------------------------------
3416 // Report if there are too many recompiles at the current method and bci.
3417 // Consults PerBytecodeRecompilationCutoff and PerMethodRecompilationCutoff.
3418 // Is not eager to return true, since this will cause the compiler to use
3419 // Action_none for a trap point, to avoid too many recompilations.
3420 bool Compile::too_many_recompiles(ciMethod* method,
3421 int bci,
3422 Deoptimization::DeoptReason reason) {
3423 ciMethodData* md = method->method_data();
3424 if (md->is_empty()) {
3425 // Assume the trap has not occurred, or that it occurred only
3426 // because of a transient condition during start-up in the interpreter.
3427 return false;
3428 }
3429 // Pick a cutoff point well within PerBytecodeRecompilationCutoff.
3430 uint bc_cutoff = (uint) PerBytecodeRecompilationCutoff / 8;
3431 uint m_cutoff = (uint) PerMethodRecompilationCutoff / 2 + 1; // not zero
3432 Deoptimization::DeoptReason per_bc_reason
3433 = Deoptimization::reason_recorded_per_bytecode_if_any(reason);
3434 ciMethod* m = Deoptimization::reason_is_speculate(reason) ? this->method() : NULL;
3435 if ((per_bc_reason == Deoptimization::Reason_none
3436 || md->has_trap_at(bci, m, reason) != 0)
3437 // The trap frequency measure we care about is the recompile count:
3438 && md->trap_recompiled_at(bci, m)
3439 && md->overflow_recompile_count() >= bc_cutoff) {
3440 // Do not emit a trap here if it has already caused recompilations.
3441 // Also, if there are multiple reasons, or if there is no per-BCI record,
3442 // assume the worst.
3443 if (log())
3444 log()->elem("observe trap='%s recompiled' count='%d' recompiles2='%d'",
3445 Deoptimization::trap_reason_name(reason),
3446 md->trap_count(reason),
3447 md->overflow_recompile_count());
3448 return true;
3449 } else if (trap_count(reason) != 0
3450 && decompile_count() >= m_cutoff) {
3451 // Too many recompiles globally, and we have seen this sort of trap.
3452 // Use cumulative decompile_count, not just md->decompile_count.
3453 if (log())
3454 log()->elem("observe trap='%s' count='%d' mcount='%d' decompiles='%d' mdecompiles='%d'",
3455 Deoptimization::trap_reason_name(reason),
3456 md->trap_count(reason), trap_count(reason),
3457 md->decompile_count(), decompile_count());
3458 return true;
3459 } else {
3460 // The coast is clear.
3461 return false;
3462 }
3463 }
3464
3465 // Compute when not to trap. Used by matching trap based nodes and
3466 // NullCheck optimization.
3467 void Compile::set_allowed_deopt_reasons() {
3468 _allowed_reasons = 0;
3469 if (is_method_compilation()) {
3470 for (int rs = (int)Deoptimization::Reason_none+1; rs < Compile::trapHistLength; rs++) {
3471 assert(rs < BitsPerInt, "recode bit map");
3472 if (!too_many_traps((Deoptimization::DeoptReason) rs)) {
3473 _allowed_reasons |= nth_bit(rs);
3474 }
3475 }
3476 }
3477 }
3478
3479 #ifndef PRODUCT
3480 //------------------------------verify_graph_edges---------------------------
3481 // Walk the Graph and verify that there is a one-to-one correspondence
3482 // between Use-Def edges and Def-Use edges in the graph.
3483 void Compile::verify_graph_edges(bool no_dead_code) {
3484 if (VerifyGraphEdges) {
3485 ResourceArea *area = Thread::current()->resource_area();
3486 Unique_Node_List visited(area);
3487 // Call recursive graph walk to check edges
3488 _root->verify_edges(visited);
3489 if (no_dead_code) {
3490 // Now make sure that no visited node is used by an unvisited node.
3491 bool dead_nodes = false;
3492 Unique_Node_List checked(area);
3493 while (visited.size() > 0) {
3494 Node* n = visited.pop();
3495 checked.push(n);
3496 for (uint i = 0; i < n->outcnt(); i++) {
3497 Node* use = n->raw_out(i);
3498 if (checked.member(use)) continue; // already checked
3499 if (visited.member(use)) continue; // already in the graph
3500 if (use->is_Con()) continue; // a dead ConNode is OK
3501 // At this point, we have found a dead node which is DU-reachable.
3502 if (!dead_nodes) {
3503 tty->print_cr("*** Dead nodes reachable via DU edges:");
3504 dead_nodes = true;
3505 }
3506 use->dump(2);
3507 tty->print_cr("---");
3508 checked.push(use); // No repeats; pretend it is now checked.
3509 }
3510 }
3511 assert(!dead_nodes, "using nodes must be reachable from root");
3512 }
3513 }
3514 }
3515
3516 // Verify GC barriers consistency
3517 // Currently supported:
3518 // - G1 pre-barriers (see GraphKit::g1_write_barrier_pre())
3519 void Compile::verify_barriers() {
3520 if (UseG1GC) {
3521 // Verify G1 pre-barriers
3522 const int marking_offset = in_bytes(JavaThread::satb_mark_queue_offset() + PtrQueue::byte_offset_of_active());
3523
3524 ResourceArea *area = Thread::current()->resource_area();
3525 Unique_Node_List visited(area);
3526 Node_List worklist(area);
3527 // We're going to walk control flow backwards starting from the Root
3528 worklist.push(_root);
3529 while (worklist.size() > 0) {
3530 Node* x = worklist.pop();
3531 if (x == NULL || x == top()) continue;
3532 if (visited.member(x)) {
3533 continue;
3534 } else {
3535 visited.push(x);
3536 }
3537
3538 if (x->is_Region()) {
3539 for (uint i = 1; i < x->req(); i++) {
3540 worklist.push(x->in(i));
3541 }
3542 } else {
3543 worklist.push(x->in(0));
3544 // We are looking for the pattern:
3545 // /->ThreadLocal
3546 // If->Bool->CmpI->LoadB->AddP->ConL(marking_offset)
3547 // \->ConI(0)
3548 // We want to verify that the If and the LoadB have the same control
3549 // See GraphKit::g1_write_barrier_pre()
3550 if (x->is_If()) {
3551 IfNode *iff = x->as_If();
3552 if (iff->in(1)->is_Bool() && iff->in(1)->in(1)->is_Cmp()) {
3553 CmpNode *cmp = iff->in(1)->in(1)->as_Cmp();
3554 if (cmp->Opcode() == Op_CmpI && cmp->in(2)->is_Con() && cmp->in(2)->bottom_type()->is_int()->get_con() == 0
3555 && cmp->in(1)->is_Load()) {
3556 LoadNode* load = cmp->in(1)->as_Load();
3557 if (load->Opcode() == Op_LoadB && load->in(2)->is_AddP() && load->in(2)->in(2)->Opcode() == Op_ThreadLocal
3558 && load->in(2)->in(3)->is_Con()
3559 && load->in(2)->in(3)->bottom_type()->is_intptr_t()->get_con() == marking_offset) {
3560
3561 Node* if_ctrl = iff->in(0);
3562 Node* load_ctrl = load->in(0);
3563
3564 if (if_ctrl != load_ctrl) {
3565 // Skip possible CProj->NeverBranch in infinite loops
3566 if ((if_ctrl->is_Proj() && if_ctrl->Opcode() == Op_CProj)
3567 && (if_ctrl->in(0)->is_MultiBranch() && if_ctrl->in(0)->Opcode() == Op_NeverBranch)) {
3568 if_ctrl = if_ctrl->in(0)->in(0);
3569 }
3570 }
3571 assert(load_ctrl != NULL && if_ctrl == load_ctrl, "controls must match");
3572 }
3573 }
3574 }
3575 }
3576 }
3577 }
3578 }
3579 }
3580
3581 #endif
3582
3583 // The Compile object keeps track of failure reasons separately from the ciEnv.
3584 // This is required because there is not quite a 1-1 relation between the
3585 // ciEnv and its compilation task and the Compile object. Note that one
3586 // ciEnv might use two Compile objects, if C2Compiler::compile_method decides
3587 // to backtrack and retry without subsuming loads. Other than this backtracking
3588 // behavior, the Compile's failure reason is quietly copied up to the ciEnv
3589 // by the logic in C2Compiler.
3590 void Compile::record_failure(const char* reason) {
3591 if (log() != NULL) {
3592 log()->elem("failure reason='%s' phase='compile'", reason);
3593 }
3594 if (_failure_reason == NULL) {
3595 // Record the first failure reason.
3596 _failure_reason = reason;
3597 }
3598
3599 if (!C->failure_reason_is(C2Compiler::retry_no_subsuming_loads())) {
3600 C->print_method(PHASE_FAILURE);
3601 }
3602 _root = NULL; // flush the graph, too
3603 }
3604
3605 Compile::TracePhase::TracePhase(const char* name, elapsedTimer* accumulator, bool dolog)
3606 : TraceTime(NULL, accumulator, false NOT_PRODUCT( || TimeCompiler ), false),
3607 _phase_name(name), _dolog(dolog)
3608 {
3609 if (dolog) {
3610 C = Compile::current();
3611 _log = C->log();
3612 } else {
3613 C = NULL;
3614 _log = NULL;
3615 }
3616 if (_log != NULL) {
3617 _log->begin_head("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3618 _log->stamp();
3619 _log->end_head();
3620 }
3621 }
3622
3623 Compile::TracePhase::~TracePhase() {
3624
3625 C = Compile::current();
3626 if (_dolog) {
3627 _log = C->log();
3628 } else {
3629 _log = NULL;
3630 }
3631
3632 #ifdef ASSERT
3633 if (PrintIdealNodeCount) {
3634 tty->print_cr("phase name='%s' nodes='%d' live='%d' live_graph_walk='%d'",
3635 _phase_name, C->unique(), C->live_nodes(), C->count_live_nodes_by_graph_walk());
3636 }
3637
3638 if (VerifyIdealNodeCount) {
3639 Compile::current()->print_missing_nodes();
3640 }
3641 #endif
3642
3643 if (_log != NULL) {
3644 _log->done("phase name='%s' nodes='%d' live='%d'", _phase_name, C->unique(), C->live_nodes());
3645 }
3646 }
3647
3648 //=============================================================================
3649 // Two Constant's are equal when the type and the value are equal.
3650 bool Compile::Constant::operator==(const Constant& other) {
3651 if (type() != other.type() ) return false;
3652 if (can_be_reused() != other.can_be_reused()) return false;
3653 // For floating point values we compare the bit pattern.
3654 switch (type()) {
3655 case T_FLOAT: return (_v._value.i == other._v._value.i);
3656 case T_LONG:
3657 case T_DOUBLE: return (_v._value.j == other._v._value.j);
3658 case T_OBJECT:
3659 case T_ADDRESS: return (_v._value.l == other._v._value.l);
3660 case T_VOID: return (_v._value.l == other._v._value.l); // jump-table entries
3661 case T_METADATA: return (_v._metadata == other._v._metadata);
3662 default: ShouldNotReachHere();
3663 }
3664 return false;
3665 }
3666
3667 static int type_to_size_in_bytes(BasicType t) {
3668 switch (t) {
3669 case T_LONG: return sizeof(jlong );
3670 case T_FLOAT: return sizeof(jfloat );
3671 case T_DOUBLE: return sizeof(jdouble);
3672 case T_METADATA: return sizeof(Metadata*);
3673 // We use T_VOID as marker for jump-table entries (labels) which
3674 // need an internal word relocation.
3675 case T_VOID:
3676 case T_ADDRESS:
3677 case T_OBJECT: return sizeof(jobject);
3678 }
3679
3680 ShouldNotReachHere();
3681 return -1;
3682 }
3683
3684 int Compile::ConstantTable::qsort_comparator(Constant* a, Constant* b) {
3685 // sort descending
3686 if (a->freq() > b->freq()) return -1;
3687 if (a->freq() < b->freq()) return 1;
3688 return 0;
3689 }
3690
3691 void Compile::ConstantTable::calculate_offsets_and_size() {
3692 // First, sort the array by frequencies.
3693 _constants.sort(qsort_comparator);
3694
3695 #ifdef ASSERT
3696 // Make sure all jump-table entries were sorted to the end of the
3697 // array (they have a negative frequency).
3698 bool found_void = false;
3699 for (int i = 0; i < _constants.length(); i++) {
3700 Constant con = _constants.at(i);
3701 if (con.type() == T_VOID)
3702 found_void = true; // jump-tables
3703 else
3704 assert(!found_void, "wrong sorting");
3705 }
3706 #endif
3707
3708 int offset = 0;
3709 for (int i = 0; i < _constants.length(); i++) {
3710 Constant* con = _constants.adr_at(i);
3711
3712 // Align offset for type.
3713 int typesize = type_to_size_in_bytes(con->type());
3714 offset = align_size_up(offset, typesize);
3715 con->set_offset(offset); // set constant's offset
3716
3717 if (con->type() == T_VOID) {
3718 MachConstantNode* n = (MachConstantNode*) con->get_jobject();
3719 offset = offset + typesize * n->outcnt(); // expand jump-table
3720 } else {
3721 offset = offset + typesize;
3722 }
3723 }
3724
3725 // Align size up to the next section start (which is insts; see
3726 // CodeBuffer::align_at_start).
3727 assert(_size == -1, "already set?");
3728 _size = align_size_up(offset, CodeEntryAlignment);
3729 }
3730
3731 void Compile::ConstantTable::emit(CodeBuffer& cb) {
3732 MacroAssembler _masm(&cb);
3733 for (int i = 0; i < _constants.length(); i++) {
3734 Constant con = _constants.at(i);
3735 address constant_addr = NULL;
3736 switch (con.type()) {
3737 case T_LONG: constant_addr = _masm.long_constant( con.get_jlong() ); break;
3738 case T_FLOAT: constant_addr = _masm.float_constant( con.get_jfloat() ); break;
3739 case T_DOUBLE: constant_addr = _masm.double_constant(con.get_jdouble()); break;
3740 case T_OBJECT: {
3741 jobject obj = con.get_jobject();
3742 int oop_index = _masm.oop_recorder()->find_index(obj);
3743 constant_addr = _masm.address_constant((address) obj, oop_Relocation::spec(oop_index));
3744 break;
3745 }
3746 case T_ADDRESS: {
3747 address addr = (address) con.get_jobject();
3748 constant_addr = _masm.address_constant(addr);
3749 break;
3750 }
3751 // We use T_VOID as marker for jump-table entries (labels) which
3752 // need an internal word relocation.
3753 case T_VOID: {
3754 MachConstantNode* n = (MachConstantNode*) con.get_jobject();
3755 // Fill the jump-table with a dummy word. The real value is
3756 // filled in later in fill_jump_table.
3757 address dummy = (address) n;
3758 constant_addr = _masm.address_constant(dummy);
3759 // Expand jump-table
3760 for (uint i = 1; i < n->outcnt(); i++) {
3761 address temp_addr = _masm.address_constant(dummy + i);
3762 assert(temp_addr, "consts section too small");
3763 }
3764 break;
3765 }
3766 case T_METADATA: {
3767 Metadata* obj = con.get_metadata();
3768 int metadata_index = _masm.oop_recorder()->find_index(obj);
3769 constant_addr = _masm.address_constant((address) obj, metadata_Relocation::spec(metadata_index));
3770 break;
3771 }
3772 default: ShouldNotReachHere();
3773 }
3774 assert(constant_addr, "consts section too small");
3775 assert((constant_addr - _masm.code()->consts()->start()) == con.offset(),
3776 err_msg_res("must be: %d == %d", (int) (constant_addr - _masm.code()->consts()->start()), (int)(con.offset())));
3777 }
3778 }
3779
3780 int Compile::ConstantTable::find_offset(Constant& con) const {
3781 int idx = _constants.find(con);
3782 assert(idx != -1, "constant must be in constant table");
3783 int offset = _constants.at(idx).offset();
3784 assert(offset != -1, "constant table not emitted yet?");
3785 return offset;
3786 }
3787
3788 void Compile::ConstantTable::add(Constant& con) {
3789 if (con.can_be_reused()) {
3790 int idx = _constants.find(con);
3791 if (idx != -1 && _constants.at(idx).can_be_reused()) {
3792 _constants.adr_at(idx)->inc_freq(con.freq()); // increase the frequency by the current value
3793 return;
3794 }
3795 }
3796 (void) _constants.append(con);
3797 }
3798
3799 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, BasicType type, jvalue value) {
3800 Block* b = Compile::current()->cfg()->get_block_for_node(n);
3801 Constant con(type, value, b->_freq);
3802 add(con);
3803 return con;
3804 }
3805
3806 Compile::Constant Compile::ConstantTable::add(Metadata* metadata) {
3807 Constant con(metadata);
3808 add(con);
3809 return con;
3810 }
3811
3812 Compile::Constant Compile::ConstantTable::add(MachConstantNode* n, MachOper* oper) {
3813 jvalue value;
3814 BasicType type = oper->type()->basic_type();
3815 switch (type) {
3816 case T_LONG: value.j = oper->constantL(); break;
3817 case T_FLOAT: value.f = oper->constantF(); break;
3818 case T_DOUBLE: value.d = oper->constantD(); break;
3819 case T_OBJECT:
3820 case T_ADDRESS: value.l = (jobject) oper->constant(); break;
3821 case T_METADATA: return add((Metadata*)oper->constant()); break;
3822 default: guarantee(false, err_msg_res("unhandled type: %s", type2name(type)));
3823 }
3824 return add(n, type, value);
3825 }
3826
3827 Compile::Constant Compile::ConstantTable::add_jump_table(MachConstantNode* n) {
3828 jvalue value;
3829 // We can use the node pointer here to identify the right jump-table
3830 // as this method is called from Compile::Fill_buffer right before
3831 // the MachNodes are emitted and the jump-table is filled (means the
3832 // MachNode pointers do not change anymore).
3833 value.l = (jobject) n;
3834 Constant con(T_VOID, value, next_jump_table_freq(), false); // Labels of a jump-table cannot be reused.
3835 add(con);
3836 return con;
3837 }
3838
3839 void Compile::ConstantTable::fill_jump_table(CodeBuffer& cb, MachConstantNode* n, GrowableArray<Label*> labels) const {
3840 // If called from Compile::scratch_emit_size do nothing.
3841 if (Compile::current()->in_scratch_emit_size()) return;
3842
3843 assert(labels.is_nonempty(), "must be");
3844 assert((uint) labels.length() == n->outcnt(), err_msg_res("must be equal: %d == %d", labels.length(), n->outcnt()));
3845
3846 // Since MachConstantNode::constant_offset() also contains
3847 // table_base_offset() we need to subtract the table_base_offset()
3848 // to get the plain offset into the constant table.
3849 int offset = n->constant_offset() - table_base_offset();
3850
3851 MacroAssembler _masm(&cb);
3852 address* jump_table_base = (address*) (_masm.code()->consts()->start() + offset);
3853
3854 for (uint i = 0; i < n->outcnt(); i++) {
3855 address* constant_addr = &jump_table_base[i];
3856 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)));
3857 *constant_addr = cb.consts()->target(*labels.at(i), (address) constant_addr);
3858 cb.consts()->relocate((address) constant_addr, relocInfo::internal_word_type);
3859 }
3860 }
3861
3862 void Compile::dump_inlining() {
3863 if (print_inlining() || print_intrinsics()) {
3864 // Print inlining message for candidates that we couldn't inline
3865 // for lack of space or non constant receiver
3866 for (int i = 0; i < _late_inlines.length(); i++) {
3867 CallGenerator* cg = _late_inlines.at(i);
3868 cg->print_inlining_late("live nodes > LiveNodeCountInliningCutoff");
3869 }
3870 Unique_Node_List useful;
3871 useful.push(root());
3872 for (uint next = 0; next < useful.size(); ++next) {
3873 Node* n = useful.at(next);
3874 if (n->is_Call() && n->as_Call()->generator() != NULL && n->as_Call()->generator()->call_node() == n) {
3875 CallNode* call = n->as_Call();
3876 CallGenerator* cg = call->generator();
3877 cg->print_inlining_late("receiver not constant");
3878 }
3879 uint max = n->len();
3880 for ( uint i = 0; i < max; ++i ) {
3881 Node *m = n->in(i);
3882 if ( m == NULL ) continue;
3883 useful.push(m);
3884 }
3885 }
3886 for (int i = 0; i < _print_inlining_list->length(); i++) {
3887 tty->print("%s", _print_inlining_list->adr_at(i)->ss()->as_string());
3888 }
3889 }
3890 }
3891
3892 // Dump inlining replay data to the stream.
3893 // Don't change thread state and acquire any locks.
3894 void Compile::dump_inline_data(outputStream* out) {
3895 InlineTree* inl_tree = ilt();
3896 if (inl_tree != NULL) {
3897 out->print(" inline %d", inl_tree->count());
3898 inl_tree->dump_replay_data(out);
3899 }
3900 }
3901
3902 int Compile::cmp_expensive_nodes(Node* n1, Node* n2) {
3903 if (n1->Opcode() < n2->Opcode()) return -1;
3904 else if (n1->Opcode() > n2->Opcode()) return 1;
3905
3906 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()));
3907 for (uint i = 1; i < n1->req(); i++) {
3908 if (n1->in(i) < n2->in(i)) return -1;
3909 else if (n1->in(i) > n2->in(i)) return 1;
3910 }
3911
3912 return 0;
3913 }
3914
3915 int Compile::cmp_expensive_nodes(Node** n1p, Node** n2p) {
3916 Node* n1 = *n1p;
3917 Node* n2 = *n2p;
3918
3919 return cmp_expensive_nodes(n1, n2);
3920 }
3921
3922 void Compile::sort_expensive_nodes() {
3923 if (!expensive_nodes_sorted()) {
3924 _expensive_nodes->sort(cmp_expensive_nodes);
3925 }
3926 }
3927
3928 bool Compile::expensive_nodes_sorted() const {
3929 for (int i = 1; i < _expensive_nodes->length(); i++) {
3930 if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i-1)) < 0) {
3931 return false;
3932 }
3933 }
3934 return true;
3935 }
3936
3937 bool Compile::should_optimize_expensive_nodes(PhaseIterGVN &igvn) {
3938 if (_expensive_nodes->length() == 0) {
3939 return false;
3940 }
3941
3942 assert(OptimizeExpensiveOps, "optimization off?");
3943
3944 // Take this opportunity to remove dead nodes from the list
3945 int j = 0;
3946 for (int i = 0; i < _expensive_nodes->length(); i++) {
3947 Node* n = _expensive_nodes->at(i);
3948 if (!n->is_unreachable(igvn)) {
3949 assert(n->is_expensive(), "should be expensive");
3950 _expensive_nodes->at_put(j, n);
3951 j++;
3952 }
3953 }
3954 _expensive_nodes->trunc_to(j);
3955
3956 // Then sort the list so that similar nodes are next to each other
3957 // and check for at least two nodes of identical kind with same data
3958 // inputs.
3959 sort_expensive_nodes();
3960
3961 for (int i = 0; i < _expensive_nodes->length()-1; i++) {
3962 if (cmp_expensive_nodes(_expensive_nodes->adr_at(i), _expensive_nodes->adr_at(i+1)) == 0) {
3963 return true;
3964 }
3965 }
3966
3967 return false;
3968 }
3969
3970 void Compile::cleanup_expensive_nodes(PhaseIterGVN &igvn) {
3971 if (_expensive_nodes->length() == 0) {
3972 return;
3973 }
3974
3975 assert(OptimizeExpensiveOps, "optimization off?");
3976
3977 // Sort to bring similar nodes next to each other and clear the
3978 // control input of nodes for which there's only a single copy.
3979 sort_expensive_nodes();
3980
3981 int j = 0;
3982 int identical = 0;
3983 int i = 0;
3984 for (; i < _expensive_nodes->length()-1; i++) {
3985 assert(j <= i, "can't write beyond current index");
3986 if (_expensive_nodes->at(i)->Opcode() == _expensive_nodes->at(i+1)->Opcode()) {
3987 identical++;
3988 _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3989 continue;
3990 }
3991 if (identical > 0) {
3992 _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
3993 identical = 0;
3994 } else {
3995 Node* n = _expensive_nodes->at(i);
3996 igvn.hash_delete(n);
3997 n->set_req(0, NULL);
3998 igvn.hash_insert(n);
3999 }
4000 }
4001 if (identical > 0) {
4002 _expensive_nodes->at_put(j++, _expensive_nodes->at(i));
4003 } else if (_expensive_nodes->length() >= 1) {
4004 Node* n = _expensive_nodes->at(i);
4005 igvn.hash_delete(n);
4006 n->set_req(0, NULL);
4007 igvn.hash_insert(n);
4008 }
4009 _expensive_nodes->trunc_to(j);
4010 }
4011
4012 void Compile::add_expensive_node(Node * n) {
4013 assert(!_expensive_nodes->contains(n), "duplicate entry in expensive list");
4014 assert(n->is_expensive(), "expensive nodes with non-null control here only");
4015 assert(!n->is_CFG() && !n->is_Mem(), "no cfg or memory nodes here");
4016 if (OptimizeExpensiveOps) {
4017 _expensive_nodes->append(n);
4018 } else {
4019 // Clear control input and let IGVN optimize expensive nodes if
4020 // OptimizeExpensiveOps is off.
4021 n->set_req(0, NULL);
4022 }
4023 }
4024
4025 /**
4026 * Remove the speculative part of types and clean up the graph
4027 */
4028 void Compile::remove_speculative_types(PhaseIterGVN &igvn) {
4029 if (UseTypeSpeculation) {
4030 Unique_Node_List worklist;
4031 worklist.push(root());
4032 int modified = 0;
4033 // Go over all type nodes that carry a speculative type, drop the
4034 // speculative part of the type and enqueue the node for an igvn
4035 // which may optimize it out.
4036 for (uint next = 0; next < worklist.size(); ++next) {
4037 Node *n = worklist.at(next);
4038 if (n->is_Type()) {
4039 TypeNode* tn = n->as_Type();
4040 const Type* t = tn->type();
4041 const Type* t_no_spec = t->remove_speculative();
4042 if (t_no_spec != t) {
4043 bool in_hash = igvn.hash_delete(n);
4044 assert(in_hash, "node should be in igvn hash table");
4045 tn->set_type(t_no_spec);
4046 igvn.hash_insert(n);
4047 igvn._worklist.push(n); // give it a chance to go away
4048 modified++;
4049 }
4050 }
4051 uint max = n->len();
4052 for( uint i = 0; i < max; ++i ) {
4053 Node *m = n->in(i);
4054 if (not_a_node(m)) continue;
4055 worklist.push(m);
4056 }
4057 }
4058 // Drop the speculative part of all types in the igvn's type table
4059 igvn.remove_speculative_types();
4060 if (modified > 0) {
4061 igvn.optimize();
4062 }
4063 #ifdef ASSERT
4064 // Verify that after the IGVN is over no speculative type has resurfaced
4065 worklist.clear();
4066 worklist.push(root());
4067 for (uint next = 0; next < worklist.size(); ++next) {
4068 Node *n = worklist.at(next);
4069 const Type* t = igvn.type_or_null(n);
4070 assert((t == NULL) || (t == t->remove_speculative()), "no more speculative types");
4071 if (n->is_Type()) {
4072 t = n->as_Type()->type();
4073 assert(t == t->remove_speculative(), "no more speculative types");
4074 }
4075 uint max = n->len();
4076 for( uint i = 0; i < max; ++i ) {
4077 Node *m = n->in(i);
4078 if (not_a_node(m)) continue;
4079 worklist.push(m);
4080 }
4081 }
4082 igvn.check_no_speculative_types();
4083 #endif
4084 }
4085 }
4086
4087 // Convert integer value to a narrowed long type dependent on ctrl (for example, a range check)
4088 Node* Compile::constrained_convI2L(PhaseGVN* phase, Node* value, const TypeInt* itype, Node* ctrl) {
4089 if (ctrl != NULL) {
4090 // Express control dependency by a CastII node with a narrow type.
4091 value = new (phase->C) CastIINode(value, itype, false, true /* range check dependency */);
4092 // Make the CastII node dependent on the control input to prevent the narrowed ConvI2L
4093 // node from floating above the range check during loop optimizations. Otherwise, the
4094 // ConvI2L node may be eliminated independently of the range check, causing the data path
4095 // to become TOP while the control path is still there (although it's unreachable).
4096 value->set_req(0, ctrl);
4097 // Save CastII node to remove it after loop optimizations.
4098 phase->C->add_range_check_cast(value);
4099 value = phase->transform(value);
4100 }
4101 const TypeLong* ltype = TypeLong::make(itype->_lo, itype->_hi, itype->_widen);
4102 return phase->transform(new (phase->C) ConvI2LNode(value, ltype));
4103 }
4104
4105 // Auxiliary method to support randomized stressing/fuzzing.
4106 //
4107 // This method can be called the arbitrary number of times, with current count
4108 // as the argument. The logic allows selecting a single candidate from the
4109 // running list of candidates as follows:
4110 // int count = 0;
4111 // Cand* selected = null;
4112 // while(cand = cand->next()) {
4113 // if (randomized_select(++count)) {
4114 // selected = cand;
4115 // }
4116 // }
4117 //
4118 // Including count equalizes the chances any candidate is "selected".
4119 // This is useful when we don't have the complete list of candidates to choose
4120 // from uniformly. In this case, we need to adjust the randomicity of the
4121 // selection, or else we will end up biasing the selection towards the latter
4122 // candidates.
4123 //
4124 // Quick back-envelope calculation shows that for the list of n candidates
4125 // the equal probability for the candidate to persist as "best" can be
4126 // achieved by replacing it with "next" k-th candidate with the probability
4127 // of 1/k. It can be easily shown that by the end of the run, the
4128 // probability for any candidate is converged to 1/n, thus giving the
4129 // uniform distribution among all the candidates.
4130 //
4131 // We don't care about the domain size as long as (RANDOMIZED_DOMAIN / count) is large.
4132 #define RANDOMIZED_DOMAIN_POW 29
4133 #define RANDOMIZED_DOMAIN (1 << RANDOMIZED_DOMAIN_POW)
4134 #define RANDOMIZED_DOMAIN_MASK ((1 << (RANDOMIZED_DOMAIN_POW + 1)) - 1)
4135 bool Compile::randomized_select(int count) {
4136 assert(count > 0, "only positive");
4137 return (os::random() & RANDOMIZED_DOMAIN_MASK) < (RANDOMIZED_DOMAIN / count);
4138 }