1 /*
2 * Copyright (c) 2000, 2019, 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 "classfile/classLoaderDataGraph.inline.hpp"
27 #include "code/compiledIC.hpp"
28 #include "code/nmethod.hpp"
29 #include "code/scopeDesc.hpp"
30 #include "interpreter/interpreter.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/methodData.hpp"
33 #include "oops/method.inline.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "prims/nativeLookup.hpp"
36 #include "runtime/compilationPolicy.hpp"
37 #include "runtime/frame.hpp"
38 #include "runtime/handles.inline.hpp"
39 #include "runtime/stubRoutines.hpp"
40 #include "runtime/thread.hpp"
41 #include "runtime/tieredThresholdPolicy.hpp"
42 #include "runtime/vframe.hpp"
43 #include "runtime/vmOperations.hpp"
44 #include "utilities/events.inline.hpp"
45 #include "utilities/globalDefinitions.hpp"
46
47 #ifdef COMPILER1
48 #include "c1/c1_Compiler.hpp"
49 #endif
50 #ifdef COMPILER2
51 #include "opto/c2compiler.hpp"
52 #endif
53
54 CompilationPolicy* CompilationPolicy::_policy;
55
56 // Determine compilation policy based on command line argument
57 void compilationPolicy_init() {
58 #ifdef TIERED
59 if (TieredCompilation) {
60 CompilationPolicy::set_policy(new TieredThresholdPolicy());
61 } else {
62 CompilationPolicy::set_policy(new SimpleCompPolicy());
63 }
64 #else
65 CompilationPolicy::set_policy(new SimpleCompPolicy());
66 #endif
67
68 CompilationPolicy::policy()->initialize();
69 }
70
71 // Returns true if m must be compiled before executing it
72 // This is intended to force compiles for methods (usually for
73 // debugging) that would otherwise be interpreted for some reason.
74 bool CompilationPolicy::must_be_compiled(const methodHandle& m, int comp_level) {
75 // Don't allow Xcomp to cause compiles in replay mode
76 if (ReplayCompiles) return false;
77
78 if (m->has_compiled_code()) return false; // already compiled
79 if (!can_be_compiled(m, comp_level)) return false;
80
81 return !UseInterpreter || // must compile all methods
82 (UseCompiler && AlwaysCompileLoopMethods && m->has_loops() && CompileBroker::should_compile_new_jobs()); // eagerly compile loop methods
83 }
84
85 void CompilationPolicy::compile_if_required(const methodHandle& selected_method, TRAPS) {
86 if (must_be_compiled(selected_method)) {
87 // This path is unusual, mostly used by the '-Xcomp' stress test mode.
88
89 // Note: with several active threads, the must_be_compiled may be true
90 // while can_be_compiled is false; remove assert
91 // assert(CompilationPolicy::can_be_compiled(selected_method), "cannot compile");
92 if (!THREAD->can_call_java() || THREAD->is_Compiler_thread()) {
93 // don't force compilation, resolve was on behalf of compiler
94 return;
95 }
96 if (selected_method->method_holder()->is_not_initialized()) {
97 // 'is_not_initialized' means not only '!is_initialized', but also that
98 // initialization has not been started yet ('!being_initialized')
99 // Do not force compilation of methods in uninitialized classes.
100 // Note that doing this would throw an assert later,
101 // in CompileBroker::compile_method.
102 // We sometimes use the link resolver to do reflective lookups
103 // even before classes are initialized.
104 return;
105 }
106 CompileBroker::compile_method(selected_method, InvocationEntryBci,
107 CompilationPolicy::policy()->initial_compile_level(),
108 methodHandle(), 0, CompileTask::Reason_MustBeCompiled, CHECK);
109 }
110 }
111
112 // Returns true if m is allowed to be compiled
113 bool CompilationPolicy::can_be_compiled(const methodHandle& m, int comp_level) {
114 // allow any levels for WhiteBox
115 assert(WhiteBoxAPI || comp_level == CompLevel_all || is_compile(comp_level), "illegal compilation level");
116
117 if (m->is_abstract()) return false;
118 if (DontCompileHugeMethods && m->code_size() > HugeMethodLimit) return false;
119
120 // Math intrinsics should never be compiled as this can lead to
121 // monotonicity problems because the interpreter will prefer the
122 // compiled code to the intrinsic version. This can't happen in
123 // production because the invocation counter can't be incremented
124 // but we shouldn't expose the system to this problem in testing
125 // modes.
126 if (!AbstractInterpreter::can_be_compiled(m)) {
127 return false;
128 }
129 if (comp_level == CompLevel_all) {
130 if (TieredCompilation) {
131 // enough to be compilable at any level for tiered
132 return !m->is_not_compilable(CompLevel_simple) || !m->is_not_compilable(CompLevel_full_optimization);
133 } else {
134 // must be compilable at available level for non-tiered
135 return !m->is_not_compilable(CompLevel_highest_tier);
136 }
137 } else if (is_compile(comp_level)) {
138 return !m->is_not_compilable(comp_level);
139 }
140 return false;
141 }
142
143 // Returns true if m is allowed to be osr compiled
144 bool CompilationPolicy::can_be_osr_compiled(const methodHandle& m, int comp_level) {
145 bool result = false;
146 if (comp_level == CompLevel_all) {
147 if (TieredCompilation) {
148 // enough to be osr compilable at any level for tiered
149 result = !m->is_not_osr_compilable(CompLevel_simple) || !m->is_not_osr_compilable(CompLevel_full_optimization);
150 } else {
151 // must be osr compilable at available level for non-tiered
152 result = !m->is_not_osr_compilable(CompLevel_highest_tier);
153 }
154 } else if (is_compile(comp_level)) {
155 result = !m->is_not_osr_compilable(comp_level);
156 }
157 return (result && can_be_compiled(m, comp_level));
158 }
159
160 bool CompilationPolicy::is_compilation_enabled() {
161 // NOTE: CompileBroker::should_compile_new_jobs() checks for UseCompiler
162 return CompileBroker::should_compile_new_jobs();
163 }
164
165 CompileTask* CompilationPolicy::select_task_helper(CompileQueue* compile_queue) {
166 // Remove unloaded methods from the queue
167 for (CompileTask* task = compile_queue->first(); task != NULL; ) {
168 CompileTask* next = task->next();
169 if (task->is_unloaded()) {
170 compile_queue->remove_and_mark_stale(task);
171 }
172 task = next;
173 }
174 #if INCLUDE_JVMCI
175 if (UseJVMCICompiler && !BackgroundCompilation) {
176 /*
177 * In blocking compilation mode, the CompileBroker will make
178 * compilations submitted by a JVMCI compiler thread non-blocking. These
179 * compilations should be scheduled after all blocking compilations
180 * to service non-compiler related compilations sooner and reduce the
181 * chance of such compilations timing out.
182 */
183 for (CompileTask* task = compile_queue->first(); task != NULL; task = task->next()) {
184 if (task->is_blocking()) {
185 return task;
186 }
187 }
188 }
189 #endif
190 return compile_queue->first();
191 }
192
193 #ifndef PRODUCT
194 void SimpleCompPolicy::trace_osr_completion(nmethod* osr_nm) {
195 if (TraceOnStackReplacement) {
196 if (osr_nm == NULL) tty->print_cr("compilation failed");
197 else tty->print_cr("nmethod " INTPTR_FORMAT, p2i(osr_nm));
198 }
199 }
200 #endif // !PRODUCT
201
202 void SimpleCompPolicy::initialize() {
203 // Setup the compiler thread numbers
204 if (CICompilerCountPerCPU) {
205 // Example: if CICompilerCountPerCPU is true, then we get
206 // max(log2(8)-1,1) = 2 compiler threads on an 8-way machine.
207 // May help big-app startup time.
208 _compiler_count = MAX2(log2_int(os::active_processor_count())-1,1);
209 // Make sure there is enough space in the code cache to hold all the compiler buffers
210 size_t buffer_size = 1;
211 #ifdef COMPILER1
212 buffer_size = is_client_compilation_mode_vm() ? Compiler::code_buffer_size() : buffer_size;
213 #endif
214 #ifdef COMPILER2
215 buffer_size = is_server_compilation_mode_vm() ? C2Compiler::initial_code_buffer_size() : buffer_size;
216 #endif
217 int max_count = (ReservedCodeCacheSize - (CodeCacheMinimumUseSpace DEBUG_ONLY(* 3))) / (int)buffer_size;
218 if (_compiler_count > max_count) {
219 // Lower the compiler count such that all buffers fit into the code cache
220 _compiler_count = MAX2(max_count, 1);
221 }
222 FLAG_SET_ERGO(CICompilerCount, _compiler_count);
223 } else {
224 _compiler_count = CICompilerCount;
225 }
226 }
227
228 // Note: this policy is used ONLY if TieredCompilation is off.
229 // compiler_count() behaves the following way:
230 // - with TIERED build (with both COMPILER1 and COMPILER2 defined) it should return
231 // zero for the c1 compilation levels in server compilation mode runs
232 // and c2 compilation levels in client compilation mode runs.
233 // - with COMPILER2 not defined it should return zero for c2 compilation levels.
234 // - with COMPILER1 not defined it should return zero for c1 compilation levels.
235 // - if neither is defined - always return zero.
236 int SimpleCompPolicy::compiler_count(CompLevel comp_level) {
237 assert(!TieredCompilation, "This policy should not be used with TieredCompilation");
238 if (COMPILER2_PRESENT(is_server_compilation_mode_vm() && is_c2_compile(comp_level) ||)
239 is_client_compilation_mode_vm() && is_c1_compile(comp_level)) {
240 return _compiler_count;
241 }
242 return 0;
243 }
244
245 void SimpleCompPolicy::reset_counter_for_invocation_event(const methodHandle& m) {
246 // Make sure invocation and backedge counter doesn't overflow again right away
247 // as would be the case for native methods.
248
249 // BUT also make sure the method doesn't look like it was never executed.
250 // Set carry bit and reduce counter's value to min(count, CompileThreshold/2).
251 MethodCounters* mcs = m->method_counters();
252 assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
253 mcs->invocation_counter()->set_carry();
254 mcs->backedge_counter()->set_carry();
255
256 assert(!m->was_never_executed(), "don't reset to 0 -- could be mistaken for never-executed");
257 }
258
259 void SimpleCompPolicy::reset_counter_for_back_branch_event(const methodHandle& m) {
260 // Delay next back-branch event but pump up invocation counter to trigger
261 // whole method compilation.
262 MethodCounters* mcs = m->method_counters();
263 assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
264 InvocationCounter* i = mcs->invocation_counter();
265 InvocationCounter* b = mcs->backedge_counter();
266
267 // Don't set invocation_counter's value too low otherwise the method will
268 // look like immature (ic < ~5300) which prevents the inlining based on
269 // the type profiling.
270 i->set(i->state(), CompileThreshold);
271 // Don't reset counter too low - it is used to check if OSR method is ready.
272 b->set(b->state(), CompileThreshold / 2);
273 }
274
275 //
276 // CounterDecay
277 //
278 // Iterates through invocation counters and decrements them. This
279 // is done at each safepoint.
280 //
281 class CounterDecay : public AllStatic {
282 static jlong _last_timestamp;
283 static void do_method(Method* m) {
284 MethodCounters* mcs = m->method_counters();
285 if (mcs != NULL) {
286 mcs->invocation_counter()->decay();
287 }
288 }
289 public:
290 static void decay();
291 static bool is_decay_needed() {
292 return (os::javaTimeMillis() - _last_timestamp) > CounterDecayMinIntervalLength;
293 }
294 };
295
296 jlong CounterDecay::_last_timestamp = 0;
297
298 void CounterDecay::decay() {
299 _last_timestamp = os::javaTimeMillis();
300
301 // This operation is going to be performed only at the end of a safepoint
302 // and hence GC's will not be going on, all Java mutators are suspended
303 // at this point and hence SystemDictionary_lock is also not needed.
304 assert(SafepointSynchronize::is_at_safepoint(), "can only be executed at a safepoint");
305 size_t nclasses = ClassLoaderDataGraph::num_instance_classes();
306 size_t classes_per_tick = nclasses * (CounterDecayMinIntervalLength * 1e-3 /
307 CounterHalfLifeTime);
308 for (size_t i = 0; i < classes_per_tick; i++) {
309 InstanceKlass* k = ClassLoaderDataGraph::try_get_next_class();
310 if (k != NULL) {
311 k->methods_do(do_method);
312 }
313 }
314 }
315
316 // Called at the end of the safepoint
317 void SimpleCompPolicy::do_safepoint_work() {
318 if(UseCounterDecay && CounterDecay::is_decay_needed()) {
319 CounterDecay::decay();
320 }
321 }
322
323 void SimpleCompPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
324 ScopeDesc* sd = trap_scope;
325 MethodCounters* mcs;
326 InvocationCounter* c;
327 for (; !sd->is_top(); sd = sd->sender()) {
328 mcs = sd->method()->method_counters();
329 if (mcs != NULL) {
330 // Reset ICs of inlined methods, since they can trigger compilations also.
331 mcs->invocation_counter()->reset();
332 }
333 }
334 mcs = sd->method()->method_counters();
335 if (mcs != NULL) {
336 c = mcs->invocation_counter();
337 if (is_osr) {
338 // It was an OSR method, so bump the count higher.
339 c->set(c->state(), CompileThreshold);
340 } else {
341 c->reset();
342 }
343 mcs->backedge_counter()->reset();
344 }
345 }
346
347 // This method can be called by any component of the runtime to notify the policy
348 // that it's recommended to delay the compilation of this method.
349 void SimpleCompPolicy::delay_compilation(Method* method) {
350 MethodCounters* mcs = method->method_counters();
351 if (mcs != NULL) {
352 mcs->invocation_counter()->decay();
353 mcs->backedge_counter()->decay();
354 }
355 }
356
357 void SimpleCompPolicy::disable_compilation(Method* method) {
358 MethodCounters* mcs = method->method_counters();
359 if (mcs != NULL) {
360 mcs->invocation_counter()->set_state(InvocationCounter::wait_for_nothing);
361 mcs->backedge_counter()->set_state(InvocationCounter::wait_for_nothing);
362 }
363 }
364
365 CompileTask* SimpleCompPolicy::select_task(CompileQueue* compile_queue) {
366 return select_task_helper(compile_queue);
367 }
368
369 bool SimpleCompPolicy::is_mature(Method* method) {
370 MethodData* mdo = method->method_data();
371 assert(mdo != NULL, "Should be");
372 uint current = mdo->mileage_of(method);
373 uint initial = mdo->creation_mileage();
374 if (current < initial)
375 return true; // some sort of overflow
376 uint target;
377 if (ProfileMaturityPercentage <= 0)
378 target = (uint) -ProfileMaturityPercentage; // absolute value
379 else
380 target = (uint)( (ProfileMaturityPercentage * CompileThreshold) / 100 );
381 return (current >= initial + target);
382 }
383
384 nmethod* SimpleCompPolicy::event(const methodHandle& method, const methodHandle& inlinee, int branch_bci,
385 int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
386 assert(comp_level == CompLevel_none, "This should be only called from the interpreter");
387 NOT_PRODUCT(trace_frequency_counter_overflow(method, branch_bci, bci));
388 if (JvmtiExport::can_post_interpreter_events() && thread->is_interp_only_mode()) {
389 // If certain JVMTI events (e.g. frame pop event) are requested then the
390 // thread is forced to remain in interpreted code. This is
391 // implemented partly by a check in the run_compiled_code
392 // section of the interpreter whether we should skip running
393 // compiled code, and partly by skipping OSR compiles for
394 // interpreted-only threads.
395 if (bci != InvocationEntryBci) {
396 reset_counter_for_back_branch_event(method);
397 return NULL;
398 }
399 }
400 if (ReplayCompiles) {
401 // Don't trigger other compiles in testing mode
402 if (bci == InvocationEntryBci) {
403 reset_counter_for_invocation_event(method);
404 } else {
405 reset_counter_for_back_branch_event(method);
406 }
407 return NULL;
408 }
409
410 if (bci == InvocationEntryBci) {
411 // when code cache is full, compilation gets switched off, UseCompiler
412 // is set to false
413 if (!method->has_compiled_code() && UseCompiler) {
414 method_invocation_event(method, thread);
415 } else {
416 // Force counter overflow on method entry, even if no compilation
417 // happened. (The method_invocation_event call does this also.)
418 reset_counter_for_invocation_event(method);
419 }
420 // compilation at an invocation overflow no longer goes and retries test for
421 // compiled method. We always run the loser of the race as interpreted.
422 // so return NULL
423 return NULL;
424 } else {
425 // counter overflow in a loop => try to do on-stack-replacement
426 nmethod* osr_nm = method->lookup_osr_nmethod_for(bci, CompLevel_highest_tier, true);
427 NOT_PRODUCT(trace_osr_request(method, osr_nm, bci));
428 // when code cache is full, we should not compile any more...
429 if (osr_nm == NULL && UseCompiler) {
430 method_back_branch_event(method, bci, thread);
431 osr_nm = method->lookup_osr_nmethod_for(bci, CompLevel_highest_tier, true);
432 }
433 if (osr_nm == NULL) {
434 reset_counter_for_back_branch_event(method);
435 return NULL;
436 }
437 return osr_nm;
438 }
439 return NULL;
440 }
441
442 #ifndef PRODUCT
443 void SimpleCompPolicy::trace_frequency_counter_overflow(const methodHandle& m, int branch_bci, int bci) {
444 if (TraceInvocationCounterOverflow) {
445 MethodCounters* mcs = m->method_counters();
446 assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
447 InvocationCounter* ic = mcs->invocation_counter();
448 InvocationCounter* bc = mcs->backedge_counter();
449 ResourceMark rm;
450 if (bci == InvocationEntryBci) {
451 tty->print("comp-policy cntr ovfl @ %d in entry of ", bci);
452 } else {
453 tty->print("comp-policy cntr ovfl @ %d in loop of ", bci);
454 }
455 m->print_value();
456 tty->cr();
457 ic->print();
458 bc->print();
459 if (ProfileInterpreter) {
460 if (bci != InvocationEntryBci) {
461 MethodData* mdo = m->method_data();
462 if (mdo != NULL) {
463 ProfileData *pd = mdo->bci_to_data(branch_bci);
464 if (pd == NULL) {
465 tty->print_cr("back branch count = N/A (missing ProfileData)");
466 } else {
467 tty->print_cr("back branch count = %d", pd->as_JumpData()->taken());
468 }
469 }
470 }
471 }
472 }
473 }
474
475 void SimpleCompPolicy::trace_osr_request(const methodHandle& method, nmethod* osr, int bci) {
476 if (TraceOnStackReplacement) {
477 ResourceMark rm;
478 tty->print(osr != NULL ? "Reused OSR entry for " : "Requesting OSR entry for ");
479 method->print_short_name(tty);
480 tty->print_cr(" at bci %d", bci);
481 }
482 }
483 #endif // !PRODUCT
484
485 void SimpleCompPolicy::method_invocation_event(const methodHandle& m, JavaThread* thread) {
486 const int comp_level = CompLevel_highest_tier;
487 const int hot_count = m->invocation_count();
488 reset_counter_for_invocation_event(m);
489
490 if (is_compilation_enabled() && can_be_compiled(m, comp_level)) {
491 CompiledMethod* nm = m->code();
492 if (nm == NULL ) {
493 CompileBroker::compile_method(m, InvocationEntryBci, comp_level, m, hot_count, CompileTask::Reason_InvocationCount, thread);
494 }
495 }
496 }
497
498 void SimpleCompPolicy::method_back_branch_event(const methodHandle& m, int bci, JavaThread* thread) {
499 const int comp_level = CompLevel_highest_tier;
500 const int hot_count = m->backedge_count();
501
502 if (is_compilation_enabled() && can_be_osr_compiled(m, comp_level)) {
503 CompileBroker::compile_method(m, bci, comp_level, m, hot_count, CompileTask::Reason_BackedgeCount, thread);
504 NOT_PRODUCT(trace_osr_completion(m->lookup_osr_nmethod_for(bci, comp_level, true));)
505 }
506 }