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hotspot/src/share/vm/runtime/compilationPolicy.cpp

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+/*
+ * Copyright 2000-2007 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+# include "incls/_precompiled.incl"
+# include "incls/_compilationPolicy.cpp.incl"
+
+CompilationPolicy* CompilationPolicy::_policy;
+elapsedTimer       CompilationPolicy::_accumulated_time;
+bool               CompilationPolicy::_in_vm_startup;
+
+// Determine compilation policy based on command line argument
+void compilationPolicy_init() {
+  CompilationPolicy::set_in_vm_startup(DelayCompilationDuringStartup);
+
+  switch(CompilationPolicyChoice) {
+  case 0:
+    CompilationPolicy::set_policy(new SimpleCompPolicy());
+    break;
+
+  case 1:
+#ifdef COMPILER2
+    CompilationPolicy::set_policy(new StackWalkCompPolicy());
+#else
+    Unimplemented();
+#endif
+    break;
+
+  default:
+    fatal("CompilationPolicyChoice must be in the range: [0-1]");
+  }
+}
+
+void CompilationPolicy::completed_vm_startup() {
+  if (TraceCompilationPolicy) {
+    tty->print("CompilationPolicy: completed vm startup.\n");
+  }
+  _in_vm_startup = false;
+}
+
+// Returns true if m must be compiled before executing it
+// This is intended to force compiles for methods (usually for
+// debugging) that would otherwise be interpreted for some reason.
+bool CompilationPolicy::mustBeCompiled(methodHandle m) {
+  if (m->has_compiled_code()) return false;       // already compiled
+  if (!canBeCompiled(m))      return false;
+
+  return !UseInterpreter ||                                              // must compile all methods
+         (UseCompiler && AlwaysCompileLoopMethods && m->has_loops()); // eagerly compile loop methods
+}
+
+// Returns true if m is allowed to be compiled
+bool CompilationPolicy::canBeCompiled(methodHandle m) {
+  if (m->is_abstract()) return false;
+  if (DontCompileHugeMethods && m->code_size() > HugeMethodLimit) return false;
+
+  return !m->is_not_compilable();
+}
+
+#ifndef PRODUCT
+void CompilationPolicy::print_time() {
+  tty->print_cr ("Accumulated compilationPolicy times:");
+  tty->print_cr ("---------------------------");
+  tty->print_cr ("  Total: %3.3f sec.", _accumulated_time.seconds());
+}
+
+static void trace_osr_completion(nmethod* osr_nm) {
+  if (TraceOnStackReplacement) {
+    if (osr_nm == NULL) tty->print_cr("compilation failed");
+    else tty->print_cr("nmethod " INTPTR_FORMAT, osr_nm);
+  }
+}
+#endif // !PRODUCT
+
+void CompilationPolicy::reset_counter_for_invocation_event(methodHandle m) {
+  // Make sure invocation and backedge counter doesn't overflow again right away
+  // as would be the case for native methods.
+
+  // BUT also make sure the method doesn't look like it was never executed.
+  // Set carry bit and reduce counter's value to min(count, CompileThreshold/2).
+  m->invocation_counter()->set_carry();
+  m->backedge_counter()->set_carry();
+
+  assert(!m->was_never_executed(), "don't reset to 0 -- could be mistaken for never-executed");
+}
+
+void CompilationPolicy::reset_counter_for_back_branch_event(methodHandle m) {
+  // Delay next back-branch event but pump up invocation counter to triger
+  // whole method compilation.
+  InvocationCounter* i = m->invocation_counter();
+  InvocationCounter* b = m->backedge_counter();
+
+  // Don't set invocation_counter's value too low otherwise the method will
+  // look like immature (ic < ~5300) which prevents the inlining based on
+  // the type profiling.
+  i->set(i->state(), CompileThreshold);
+  // Don't reset counter too low - it is used to check if OSR method is ready.
+  b->set(b->state(), CompileThreshold / 2);
+}
+
+// SimpleCompPolicy - compile current method
+
+void SimpleCompPolicy::method_invocation_event( methodHandle m, TRAPS) {
+  assert(UseCompiler || CompileTheWorld, "UseCompiler should be set by now.");
+
+  int hot_count = m->invocation_count();
+  reset_counter_for_invocation_event(m);
+  const char* comment = "count";
+
+  if (!delayCompilationDuringStartup() && canBeCompiled(m) && UseCompiler) {
+    nmethod* nm = m->code();
+    if (nm == NULL ) {
+      const char* comment = "count";
+      CompileBroker::compile_method(m, InvocationEntryBci,
+                                    m, hot_count, comment, CHECK);
+    } else {
+#ifdef TIERED
+
+      if (nm->is_compiled_by_c1()) {
+        const char* comment = "tier1 overflow";
+        CompileBroker::compile_method(m, InvocationEntryBci,
+                                      m, hot_count, comment, CHECK);
+      }
+#endif // TIERED
+    }
+  }
+}
+
+void SimpleCompPolicy::method_back_branch_event(methodHandle m, int branch_bci, int loop_top_bci, TRAPS) {
+  assert(UseCompiler || CompileTheWorld, "UseCompiler should be set by now.");
+
+  int hot_count = m->backedge_count();
+  const char* comment = "backedge_count";
+
+  if (!m->is_not_osr_compilable() && !delayCompilationDuringStartup() && canBeCompiled(m)) {
+    CompileBroker::compile_method(m, loop_top_bci, m, hot_count, comment, CHECK);
+
+    NOT_PRODUCT(trace_osr_completion(m->lookup_osr_nmethod_for(loop_top_bci));)
+  }
+}
+
+int SimpleCompPolicy::compilation_level(methodHandle m, int branch_bci)
+{
+#ifdef TIERED
+  if (!TieredCompilation) {
+    return CompLevel_highest_tier;
+  }
+  if (/* m()->tier1_compile_done() && */
+     // QQQ HACK FIX ME set tier1_compile_done!!
+      !m()->is_native()) {
+    // Grab the nmethod so it doesn't go away while it's being queried
+    nmethod* code = m()->code();
+    if (code != NULL && code->is_compiled_by_c1()) {
+      return CompLevel_highest_tier;
+    }
+  }
+  return CompLevel_fast_compile;
+#else
+  return CompLevel_highest_tier;
+#endif // TIERED
+}
+
+// StackWalkCompPolicy - walk up stack to find a suitable method to compile
+
+#ifdef COMPILER2
+const char* StackWalkCompPolicy::_msg = NULL;
+
+
+// Consider m for compilation
+void StackWalkCompPolicy::method_invocation_event(methodHandle m, TRAPS) {
+  assert(UseCompiler || CompileTheWorld, "UseCompiler should be set by now.");
+
+  int hot_count = m->invocation_count();
+  reset_counter_for_invocation_event(m);
+  const char* comment = "count";
+
+  if (m->code() == NULL && !delayCompilationDuringStartup() && canBeCompiled(m) && UseCompiler) {
+    ResourceMark rm(THREAD);
+    JavaThread *thread = (JavaThread*)THREAD;
+    frame       fr     = thread->last_frame();
+    assert(fr.is_interpreted_frame(), "must be interpreted");
+    assert(fr.interpreter_frame_method() == m(), "bad method");
+
+    if (TraceCompilationPolicy) {
+      tty->print("method invocation trigger: ");
+      m->print_short_name(tty);
+      tty->print(" ( interpreted " INTPTR_FORMAT ", size=%d ) ", (address)m(), m->code_size());
+    }
+    RegisterMap reg_map(thread, false);
+    javaVFrame* triggerVF = thread->last_java_vframe(&reg_map);
+    // triggerVF is the frame that triggered its counter
+    RFrame* first = new InterpretedRFrame(triggerVF->fr(), thread, m);
+
+    if (first->top_method()->code() != NULL) {
+      // called obsolete method/nmethod -- no need to recompile
+      if (TraceCompilationPolicy) tty->print_cr(" --> " INTPTR_FORMAT, first->top_method()->code());
+    } else if (compilation_level(m, InvocationEntryBci) == CompLevel_fast_compile) {
+      // Tier1 compilation policy avaoids stack walking.
+      CompileBroker::compile_method(m, InvocationEntryBci,
+                                    m, hot_count, comment, CHECK);
+    } else {
+      if (TimeCompilationPolicy) accumulated_time()->start();
+      GrowableArray<RFrame*>* stack = new GrowableArray<RFrame*>(50);
+      stack->push(first);
+      RFrame* top = findTopInlinableFrame(stack);
+      if (TimeCompilationPolicy) accumulated_time()->stop();
+      assert(top != NULL, "findTopInlinableFrame returned null");
+      if (TraceCompilationPolicy) top->print();
+      CompileBroker::compile_method(top->top_method(), InvocationEntryBci,
+                                    m, hot_count, comment, CHECK);
+    }
+  }
+}
+
+void StackWalkCompPolicy::method_back_branch_event(methodHandle m, int branch_bci, int loop_top_bci, TRAPS) {
+  assert(UseCompiler || CompileTheWorld, "UseCompiler should be set by now.");
+
+  int hot_count = m->backedge_count();
+  const char* comment = "backedge_count";
+
+  if (!m->is_not_osr_compilable() && !delayCompilationDuringStartup() && canBeCompiled(m)) {
+    CompileBroker::compile_method(m, loop_top_bci, m, hot_count, comment, CHECK);
+
+    NOT_PRODUCT(trace_osr_completion(m->lookup_osr_nmethod_for(loop_top_bci));)
+  }
+}
+
+int StackWalkCompPolicy::compilation_level(methodHandle m, int osr_bci)
+{
+  int comp_level = CompLevel_full_optimization;
+  if (TieredCompilation && osr_bci == InvocationEntryBci) {
+    if (CompileTheWorld) {
+      // Under CTW, the first compile is tier1, the second tier2
+      if (m->highest_tier_compile() == CompLevel_none) {
+        comp_level = CompLevel_fast_compile;
+      }
+    } else if (!m->has_osr_nmethod()) {
+      // Before tier1 is done, use invocation_count + backedge_count to
+      // compare against the threshold.  After that, the counters may/will
+      // be reset, so rely on the straight interpreter_invocation_count.
+      if (m->highest_tier_compile() == CompLevel_initial_compile) {
+        if (m->interpreter_invocation_count() < Tier2CompileThreshold) {
+          comp_level = CompLevel_fast_compile;
+        }
+      } else if (m->invocation_count() + m->backedge_count() <
+                 Tier2CompileThreshold) {
+        comp_level = CompLevel_fast_compile;
+      }
+    }
+
+  }
+  return comp_level;
+}
+
+
+RFrame* StackWalkCompPolicy::findTopInlinableFrame(GrowableArray<RFrame*>* stack) {
+  // go up the stack until finding a frame that (probably) won't be inlined
+  // into its caller
+  RFrame* current = stack->at(0); // current choice for stopping
+  assert( current && !current->is_compiled(), "" );
+  const char* msg = NULL;
+
+  while (1) {
+
+    // before going up the stack further, check if doing so would get us into
+    // compiled code
+    RFrame* next = senderOf(current, stack);
+    if( !next )               // No next frame up the stack?
+      break;                  // Then compile with current frame
+
+    methodHandle m = current->top_method();
+    methodHandle next_m = next->top_method();
+
+    if (TraceCompilationPolicy && Verbose) {
+      tty->print("[caller: ");
+      next_m->print_short_name(tty);
+      tty->print("] ");
+    }
+
+    if( !Inline ) {           // Inlining turned off
+      msg = "Inlining turned off";
+      break;
+    }
+    if (next_m->is_not_compilable()) { // Did fail to compile this before/
+      msg = "caller not compilable";
+      break;
+    }
+    if (next->num() > MaxRecompilationSearchLength) {
+      // don't go up too high when searching for recompilees
+      msg = "don't go up any further: > MaxRecompilationSearchLength";
+      break;
+    }
+    if (next->distance() > MaxInterpretedSearchLength) {
+      // don't go up too high when searching for recompilees
+      msg = "don't go up any further: next > MaxInterpretedSearchLength";
+      break;
+    }
+    // Compiled frame above already decided not to inline;
+    // do not recompile him.
+    if (next->is_compiled()) {
+      msg = "not going up into optimized code";
+      break;
+    }
+
+    // Interpreted frame above us was already compiled.  Do not force
+    // a recompile, although if the frame above us runs long enough an
+    // OSR might still happen.
+    if( current->is_interpreted() && next_m->has_compiled_code() ) {
+      msg = "not going up -- already compiled caller";
+      break;
+    }
+
+    // Compute how frequent this call site is.  We have current method 'm'.
+    // We know next method 'next_m' is interpreted.  Find the call site and
+    // check the various invocation counts.
+    int invcnt = 0;             // Caller counts
+    if (ProfileInterpreter) {
+      invcnt = next_m->interpreter_invocation_count();
+    }
+    int cnt = 0;                // Call site counts
+    if (ProfileInterpreter && next_m->method_data() != NULL) {
+      ResourceMark rm;
+      int bci = next->top_vframe()->bci();
+      ProfileData* data = next_m->method_data()->bci_to_data(bci);
+      if (data != NULL && data->is_CounterData())
+        cnt = data->as_CounterData()->count();
+    }
+
+    // Caller counts / call-site counts; i.e. is this call site
+    // a hot call site for method next_m?
+    int freq = (invcnt) ? cnt/invcnt : cnt;
+
+    // Check size and frequency limits
+    if ((msg = shouldInline(m, freq, cnt)) != NULL) {
+      break;
+    }
+    // Check inlining negative tests
+    if ((msg = shouldNotInline(m)) != NULL) {
+      break;
+    }
+
+
+    // If the caller method is too big or something then we do not want to
+    // compile it just to inline a method
+    if (!canBeCompiled(next_m)) {
+      msg = "caller cannot be compiled";
+      break;
+    }
+
+    if( next_m->name() == vmSymbols::class_initializer_name() ) {
+      msg = "do not compile class initializer (OSR ok)";
+      break;
+    }
+
+    if (TraceCompilationPolicy && Verbose) {
+      tty->print("\n\t     check caller: ");
+      next_m->print_short_name(tty);
+      tty->print(" ( interpreted " INTPTR_FORMAT ", size=%d ) ", (address)next_m(), next_m->code_size());
+    }
+
+    current = next;
+  }
+
+  assert( !current || !current->is_compiled(), "" );
+
+  if (TraceCompilationPolicy && msg) tty->print("(%s)\n", msg);
+
+  return current;
+}
+
+RFrame* StackWalkCompPolicy::senderOf(RFrame* rf, GrowableArray<RFrame*>* stack) {
+  RFrame* sender = rf->caller();
+  if (sender && sender->num() == stack->length()) stack->push(sender);
+  return sender;
+}
+
+
+const char* StackWalkCompPolicy::shouldInline(methodHandle m, float freq, int cnt) {
+  // Allows targeted inlining
+  // positive filter: should send be inlined?  returns NULL (--> yes)
+  // or rejection msg
+  int max_size = MaxInlineSize;
+  int cost = m->code_size();
+
+  // Check for too many throws (and not too huge)
+  if (m->interpreter_throwout_count() > InlineThrowCount && cost < InlineThrowMaxSize ) {
+    return NULL;
+  }
+
+  // bump the max size if the call is frequent
+  if ((freq >= InlineFrequencyRatio) || (cnt >= InlineFrequencyCount)) {
+    if (TraceFrequencyInlining) {
+      tty->print("(Inlined frequent method)\n");
+      m->print();
+    }
+    max_size = FreqInlineSize;
+  }
+  if (cost > max_size) {
+    return (_msg = "too big");
+  }
+  return NULL;
+}
+
+
+const char* StackWalkCompPolicy::shouldNotInline(methodHandle m) {
+  // negative filter: should send NOT be inlined?  returns NULL (--> inline) or rejection msg
+  if (m->is_abstract()) return (_msg = "abstract method");
+  // note: we allow ik->is_abstract()
+  if (!instanceKlass::cast(m->method_holder())->is_initialized()) return (_msg = "method holder not initialized");
+  if (m->is_native()) return (_msg = "native method");
+  nmethod* m_code = m->code();
+  if( m_code != NULL && m_code->instructions_size() > InlineSmallCode )
+    return (_msg = "already compiled into a big method");
+
+  // use frequency-based objections only for non-trivial methods
+  if (m->code_size() <= MaxTrivialSize) return NULL;
+  if (UseInterpreter) {     // don't use counts with -Xcomp
+    if ((m->code() == NULL) && m->was_never_executed()) return (_msg = "never executed");
+    if (!m->was_executed_more_than(MIN2(MinInliningThreshold, CompileThreshold >> 1))) return (_msg = "executed < MinInliningThreshold times");
+  }
+  if (methodOopDesc::has_unloaded_classes_in_signature(m, JavaThread::current())) return (_msg = "unloaded signature classes");
+
+  return NULL;
+}
+
+
+
+#endif // COMPILER2