src/hotspot/share/runtime/compilationPolicy.cpp
changeset 47216 71c04702a3d5
parent 46739 89569d6a77c0
child 48418 2207e2917a68
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/runtime/compilationPolicy.cpp	Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,742 @@
+/*
+ * Copyright (c) 2000, 2017, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+
+#include "precompiled.hpp"
+#include "code/compiledIC.hpp"
+#include "code/nmethod.hpp"
+#include "code/scopeDesc.hpp"
+#include "interpreter/interpreter.hpp"
+#include "memory/resourceArea.hpp"
+#include "oops/methodData.hpp"
+#include "oops/method.hpp"
+#include "oops/oop.inline.hpp"
+#include "prims/nativeLookup.hpp"
+#include "runtime/advancedThresholdPolicy.hpp"
+#include "runtime/compilationPolicy.hpp"
+#include "runtime/frame.hpp"
+#include "runtime/handles.inline.hpp"
+#include "runtime/rframe.hpp"
+#include "runtime/simpleThresholdPolicy.hpp"
+#include "runtime/stubRoutines.hpp"
+#include "runtime/thread.hpp"
+#include "runtime/timer.hpp"
+#include "runtime/vframe.hpp"
+#include "runtime/vm_operations.hpp"
+#include "utilities/events.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+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;
+  case 2:
+#ifdef TIERED
+    CompilationPolicy::set_policy(new SimpleThresholdPolicy());
+#else
+    Unimplemented();
+#endif
+    break;
+  case 3:
+#ifdef TIERED
+    CompilationPolicy::set_policy(new AdvancedThresholdPolicy());
+#else
+    Unimplemented();
+#endif
+    break;
+  default:
+    fatal("CompilationPolicyChoice must be in the range: [0-3]");
+  }
+  CompilationPolicy::policy()->initialize();
+}
+
+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::must_be_compiled(const methodHandle& m, int comp_level) {
+  // Don't allow Xcomp to cause compiles in replay mode
+  if (ReplayCompiles) return false;
+
+  if (m->has_compiled_code()) return false;       // already compiled
+  if (!can_be_compiled(m, comp_level)) return false;
+
+  return !UseInterpreter ||                                              // must compile all methods
+         (UseCompiler && AlwaysCompileLoopMethods && m->has_loops() && CompileBroker::should_compile_new_jobs()); // eagerly compile loop methods
+}
+
+void CompilationPolicy::compile_if_required(const methodHandle& selected_method, TRAPS) {
+  if (must_be_compiled(selected_method)) {
+    // This path is unusual, mostly used by the '-Xcomp' stress test mode.
+
+    // Note: with several active threads, the must_be_compiled may be true
+    //       while can_be_compiled is false; remove assert
+    // assert(CompilationPolicy::can_be_compiled(selected_method), "cannot compile");
+    if (!THREAD->can_call_java() || THREAD->is_Compiler_thread()) {
+      // don't force compilation, resolve was on behalf of compiler
+      return;
+    }
+    if (selected_method->method_holder()->is_not_initialized()) {
+      // 'is_not_initialized' means not only '!is_initialized', but also that
+      // initialization has not been started yet ('!being_initialized')
+      // Do not force compilation of methods in uninitialized classes.
+      // Note that doing this would throw an assert later,
+      // in CompileBroker::compile_method.
+      // We sometimes use the link resolver to do reflective lookups
+      // even before classes are initialized.
+      return;
+    }
+    CompileBroker::compile_method(selected_method, InvocationEntryBci,
+        CompilationPolicy::policy()->initial_compile_level(),
+        methodHandle(), 0, CompileTask::Reason_MustBeCompiled, CHECK);
+  }
+}
+
+// Returns true if m is allowed to be compiled
+bool CompilationPolicy::can_be_compiled(const methodHandle& m, int comp_level) {
+  // allow any levels for WhiteBox
+  assert(WhiteBoxAPI || comp_level == CompLevel_all || is_compile(comp_level), "illegal compilation level");
+
+  if (m->is_abstract()) return false;
+  if (DontCompileHugeMethods && m->code_size() > HugeMethodLimit) return false;
+
+  // Math intrinsics should never be compiled as this can lead to
+  // monotonicity problems because the interpreter will prefer the
+  // compiled code to the intrinsic version.  This can't happen in
+  // production because the invocation counter can't be incremented
+  // but we shouldn't expose the system to this problem in testing
+  // modes.
+  if (!AbstractInterpreter::can_be_compiled(m)) {
+    return false;
+  }
+  if (comp_level == CompLevel_all) {
+    if (TieredCompilation) {
+      // enough to be compilable at any level for tiered
+      return !m->is_not_compilable(CompLevel_simple) || !m->is_not_compilable(CompLevel_full_optimization);
+    } else {
+      // must be compilable at available level for non-tiered
+      return !m->is_not_compilable(CompLevel_highest_tier);
+    }
+  } else if (is_compile(comp_level)) {
+    return !m->is_not_compilable(comp_level);
+  }
+  return false;
+}
+
+// Returns true if m is allowed to be osr compiled
+bool CompilationPolicy::can_be_osr_compiled(const methodHandle& m, int comp_level) {
+  bool result = false;
+  if (comp_level == CompLevel_all) {
+    if (TieredCompilation) {
+      // enough to be osr compilable at any level for tiered
+      result = !m->is_not_osr_compilable(CompLevel_simple) || !m->is_not_osr_compilable(CompLevel_full_optimization);
+    } else {
+      // must be osr compilable at available level for non-tiered
+      result = !m->is_not_osr_compilable(CompLevel_highest_tier);
+    }
+  } else if (is_compile(comp_level)) {
+    result = !m->is_not_osr_compilable(comp_level);
+  }
+  return (result && can_be_compiled(m, comp_level));
+}
+
+bool CompilationPolicy::is_compilation_enabled() {
+  // NOTE: CompileBroker::should_compile_new_jobs() checks for UseCompiler
+  return !delay_compilation_during_startup() && CompileBroker::should_compile_new_jobs();
+}
+
+CompileTask* CompilationPolicy::select_task_helper(CompileQueue* compile_queue) {
+#if INCLUDE_JVMCI
+  if (UseJVMCICompiler && !BackgroundCompilation) {
+    /*
+     * In blocking compilation mode, the CompileBroker will make
+     * compilations submitted by a JVMCI compiler thread non-blocking. These
+     * compilations should be scheduled after all blocking compilations
+     * to service non-compiler related compilations sooner and reduce the
+     * chance of such compilations timing out.
+     */
+    for (CompileTask* task = compile_queue->first(); task != NULL; task = task->next()) {
+      if (task->is_blocking()) {
+        return task;
+      }
+    }
+  }
+#endif
+  return compile_queue->first();
+}
+
+#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());
+}
+
+void NonTieredCompPolicy::trace_osr_completion(nmethod* osr_nm) {
+  if (TraceOnStackReplacement) {
+    if (osr_nm == NULL) tty->print_cr("compilation failed");
+    else tty->print_cr("nmethod " INTPTR_FORMAT, p2i(osr_nm));
+  }
+}
+#endif // !PRODUCT
+
+void NonTieredCompPolicy::initialize() {
+  // Setup the compiler thread numbers
+  if (CICompilerCountPerCPU) {
+    // Example: if CICompilerCountPerCPU is true, then we get
+    // max(log2(8)-1,1) = 2 compiler threads on an 8-way machine.
+    // May help big-app startup time.
+    _compiler_count = MAX2(log2_intptr(os::active_processor_count())-1,1);
+    FLAG_SET_ERGO(intx, CICompilerCount, _compiler_count);
+  } else {
+    _compiler_count = CICompilerCount;
+  }
+}
+
+// Note: this policy is used ONLY if TieredCompilation is off.
+// compiler_count() behaves the following way:
+// - with TIERED build (with both COMPILER1 and COMPILER2 defined) it should return
+//   zero for the c1 compilation levels in server compilation mode runs
+//   and c2 compilation levels in client compilation mode runs.
+// - with COMPILER2 not defined it should return zero for c2 compilation levels.
+// - with COMPILER1 not defined it should return zero for c1 compilation levels.
+// - if neither is defined - always return zero.
+int NonTieredCompPolicy::compiler_count(CompLevel comp_level) {
+  assert(!TieredCompilation, "This policy should not be used with TieredCompilation");
+  if (COMPILER2_PRESENT(is_server_compilation_mode_vm() && is_c2_compile(comp_level) ||)
+      is_client_compilation_mode_vm() && is_c1_compile(comp_level)) {
+    return _compiler_count;
+  }
+  return 0;
+}
+
+void NonTieredCompPolicy::reset_counter_for_invocation_event(const 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).
+  MethodCounters* mcs = m->method_counters();
+  assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
+  mcs->invocation_counter()->set_carry();
+  mcs->backedge_counter()->set_carry();
+
+  assert(!m->was_never_executed(), "don't reset to 0 -- could be mistaken for never-executed");
+}
+
+void NonTieredCompPolicy::reset_counter_for_back_branch_event(const methodHandle& m) {
+  // Delay next back-branch event but pump up invocation counter to trigger
+  // whole method compilation.
+  MethodCounters* mcs = m->method_counters();
+  assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
+  InvocationCounter* i = mcs->invocation_counter();
+  InvocationCounter* b = mcs->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);
+}
+
+//
+// CounterDecay
+//
+// Iterates through invocation counters and decrements them. This
+// is done at each safepoint.
+//
+class CounterDecay : public AllStatic {
+  static jlong _last_timestamp;
+  static void do_method(Method* m) {
+    MethodCounters* mcs = m->method_counters();
+    if (mcs != NULL) {
+      mcs->invocation_counter()->decay();
+    }
+  }
+public:
+  static void decay();
+  static bool is_decay_needed() {
+    return (os::javaTimeMillis() - _last_timestamp) > CounterDecayMinIntervalLength;
+  }
+};
+
+jlong CounterDecay::_last_timestamp = 0;
+
+void CounterDecay::decay() {
+  _last_timestamp = os::javaTimeMillis();
+
+  // This operation is going to be performed only at the end of a safepoint
+  // and hence GC's will not be going on, all Java mutators are suspended
+  // at this point and hence SystemDictionary_lock is also not needed.
+  assert(SafepointSynchronize::is_at_safepoint(), "can only be executed at a safepoint");
+  int nclasses = InstanceKlass::number_of_instance_classes();
+  int classes_per_tick = nclasses * (CounterDecayMinIntervalLength * 1e-3 /
+                                        CounterHalfLifeTime);
+  for (int i = 0; i < classes_per_tick; i++) {
+    InstanceKlass* k = ClassLoaderDataGraph::try_get_next_class();
+    if (k != NULL) {
+      k->methods_do(do_method);
+    }
+  }
+}
+
+// Called at the end of the safepoint
+void NonTieredCompPolicy::do_safepoint_work() {
+  if(UseCounterDecay && CounterDecay::is_decay_needed()) {
+    CounterDecay::decay();
+  }
+}
+
+void NonTieredCompPolicy::reprofile(ScopeDesc* trap_scope, bool is_osr) {
+  ScopeDesc* sd = trap_scope;
+  MethodCounters* mcs;
+  InvocationCounter* c;
+  for (; !sd->is_top(); sd = sd->sender()) {
+    mcs = sd->method()->method_counters();
+    if (mcs != NULL) {
+      // Reset ICs of inlined methods, since they can trigger compilations also.
+      mcs->invocation_counter()->reset();
+    }
+  }
+  mcs = sd->method()->method_counters();
+  if (mcs != NULL) {
+    c = mcs->invocation_counter();
+    if (is_osr) {
+      // It was an OSR method, so bump the count higher.
+      c->set(c->state(), CompileThreshold);
+    } else {
+      c->reset();
+    }
+    mcs->backedge_counter()->reset();
+  }
+}
+
+// This method can be called by any component of the runtime to notify the policy
+// that it's recommended to delay the compilation of this method.
+void NonTieredCompPolicy::delay_compilation(Method* method) {
+  MethodCounters* mcs = method->method_counters();
+  if (mcs != NULL) {
+    mcs->invocation_counter()->decay();
+    mcs->backedge_counter()->decay();
+  }
+}
+
+void NonTieredCompPolicy::disable_compilation(Method* method) {
+  MethodCounters* mcs = method->method_counters();
+  if (mcs != NULL) {
+    mcs->invocation_counter()->set_state(InvocationCounter::wait_for_nothing);
+    mcs->backedge_counter()->set_state(InvocationCounter::wait_for_nothing);
+  }
+}
+
+CompileTask* NonTieredCompPolicy::select_task(CompileQueue* compile_queue) {
+  return select_task_helper(compile_queue);
+}
+
+bool NonTieredCompPolicy::is_mature(Method* method) {
+  MethodData* mdo = method->method_data();
+  assert(mdo != NULL, "Should be");
+  uint current = mdo->mileage_of(method);
+  uint initial = mdo->creation_mileage();
+  if (current < initial)
+    return true;  // some sort of overflow
+  uint target;
+  if (ProfileMaturityPercentage <= 0)
+    target = (uint) -ProfileMaturityPercentage;  // absolute value
+  else
+    target = (uint)( (ProfileMaturityPercentage * CompileThreshold) / 100 );
+  return (current >= initial + target);
+}
+
+nmethod* NonTieredCompPolicy::event(const methodHandle& method, const methodHandle& inlinee, int branch_bci,
+                                    int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) {
+  assert(comp_level == CompLevel_none, "This should be only called from the interpreter");
+  NOT_PRODUCT(trace_frequency_counter_overflow(method, branch_bci, bci));
+  if (JvmtiExport::can_post_interpreter_events() && thread->is_interp_only_mode()) {
+    // If certain JVMTI events (e.g. frame pop event) are requested then the
+    // thread is forced to remain in interpreted code. This is
+    // implemented partly by a check in the run_compiled_code
+    // section of the interpreter whether we should skip running
+    // compiled code, and partly by skipping OSR compiles for
+    // interpreted-only threads.
+    if (bci != InvocationEntryBci) {
+      reset_counter_for_back_branch_event(method);
+      return NULL;
+    }
+  }
+  if (CompileTheWorld || ReplayCompiles) {
+    // Don't trigger other compiles in testing mode
+    if (bci == InvocationEntryBci) {
+      reset_counter_for_invocation_event(method);
+    } else {
+      reset_counter_for_back_branch_event(method);
+    }
+    return NULL;
+  }
+
+  if (bci == InvocationEntryBci) {
+    // when code cache is full, compilation gets switched off, UseCompiler
+    // is set to false
+    if (!method->has_compiled_code() && UseCompiler) {
+      method_invocation_event(method, thread);
+    } else {
+      // Force counter overflow on method entry, even if no compilation
+      // happened.  (The method_invocation_event call does this also.)
+      reset_counter_for_invocation_event(method);
+    }
+    // compilation at an invocation overflow no longer goes and retries test for
+    // compiled method. We always run the loser of the race as interpreted.
+    // so return NULL
+    return NULL;
+  } else {
+    // counter overflow in a loop => try to do on-stack-replacement
+    nmethod* osr_nm = method->lookup_osr_nmethod_for(bci, CompLevel_highest_tier, true);
+    NOT_PRODUCT(trace_osr_request(method, osr_nm, bci));
+    // when code cache is full, we should not compile any more...
+    if (osr_nm == NULL && UseCompiler) {
+      method_back_branch_event(method, bci, thread);
+      osr_nm = method->lookup_osr_nmethod_for(bci, CompLevel_highest_tier, true);
+    }
+    if (osr_nm == NULL) {
+      reset_counter_for_back_branch_event(method);
+      return NULL;
+    }
+    return osr_nm;
+  }
+  return NULL;
+}
+
+#ifndef PRODUCT
+void NonTieredCompPolicy::trace_frequency_counter_overflow(const methodHandle& m, int branch_bci, int bci) {
+  if (TraceInvocationCounterOverflow) {
+    MethodCounters* mcs = m->method_counters();
+    assert(mcs != NULL, "MethodCounters cannot be NULL for profiling");
+    InvocationCounter* ic = mcs->invocation_counter();
+    InvocationCounter* bc = mcs->backedge_counter();
+    ResourceMark rm;
+    if (bci == InvocationEntryBci) {
+      tty->print("comp-policy cntr ovfl @ %d in entry of ", bci);
+    } else {
+      tty->print("comp-policy cntr ovfl @ %d in loop of ", bci);
+    }
+    m->print_value();
+    tty->cr();
+    ic->print();
+    bc->print();
+    if (ProfileInterpreter) {
+      if (bci != InvocationEntryBci) {
+        MethodData* mdo = m->method_data();
+        if (mdo != NULL) {
+          int count = mdo->bci_to_data(branch_bci)->as_JumpData()->taken();
+          tty->print_cr("back branch count = %d", count);
+        }
+      }
+    }
+  }
+}
+
+void NonTieredCompPolicy::trace_osr_request(const methodHandle& method, nmethod* osr, int bci) {
+  if (TraceOnStackReplacement) {
+    ResourceMark rm;
+    tty->print(osr != NULL ? "Reused OSR entry for " : "Requesting OSR entry for ");
+    method->print_short_name(tty);
+    tty->print_cr(" at bci %d", bci);
+  }
+}
+#endif // !PRODUCT
+
+// SimpleCompPolicy - compile current method
+
+void SimpleCompPolicy::method_invocation_event(const methodHandle& m, JavaThread* thread) {
+  const int comp_level = CompLevel_highest_tier;
+  const int hot_count = m->invocation_count();
+  reset_counter_for_invocation_event(m);
+
+  if (is_compilation_enabled() && can_be_compiled(m, comp_level)) {
+    CompiledMethod* nm = m->code();
+    if (nm == NULL ) {
+      CompileBroker::compile_method(m, InvocationEntryBci, comp_level, m, hot_count, CompileTask::Reason_InvocationCount, thread);
+    }
+  }
+}
+
+void SimpleCompPolicy::method_back_branch_event(const methodHandle& m, int bci, JavaThread* thread) {
+  const int comp_level = CompLevel_highest_tier;
+  const int hot_count = m->backedge_count();
+
+  if (is_compilation_enabled() && can_be_osr_compiled(m, comp_level)) {
+    CompileBroker::compile_method(m, bci, comp_level, m, hot_count, CompileTask::Reason_BackedgeCount, thread);
+    NOT_PRODUCT(trace_osr_completion(m->lookup_osr_nmethod_for(bci, comp_level, true));)
+  }
+}
+// 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(const methodHandle& m, JavaThread* thread) {
+  const int comp_level = CompLevel_highest_tier;
+  const int hot_count = m->invocation_count();
+  reset_counter_for_invocation_event(m);
+
+  if (is_compilation_enabled() && m->code() == NULL && can_be_compiled(m, comp_level)) {
+    ResourceMark rm(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 ) ", p2i((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, p2i(first->top_method()->code()));
+    } 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, comp_level,
+                                    m, hot_count, CompileTask::Reason_InvocationCount, thread);
+    }
+  }
+}
+
+void StackWalkCompPolicy::method_back_branch_event(const methodHandle& m, int bci, JavaThread* thread) {
+  const int comp_level = CompLevel_highest_tier;
+  const int hot_count = m->backedge_count();
+
+  if (is_compilation_enabled() && can_be_osr_compiled(m, comp_level)) {
+    CompileBroker::compile_method(m, bci, comp_level, m, hot_count, CompileTask::Reason_BackedgeCount, thread);
+    NOT_PRODUCT(trace_osr_completion(m->lookup_osr_nmethod_for(bci, comp_level, true));)
+  }
+}
+
+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
+
+    Method* m = current->top_method();
+    Method* 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 (!can_be_compiled(next_m, CompLevel_any)) {
+      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 ) ", p2i((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(const 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(const 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 (!m->method_holder()->is_initialized()) return (_msg = "method holder not initialized");
+  if (m->is_native()) return (_msg = "native method");
+  CompiledMethod* m_code = m->code();
+  if (m_code != NULL && m_code->code_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 (Method::has_unloaded_classes_in_signature(m, JavaThread::current())) return (_msg = "unloaded signature classes");
+
+  return NULL;
+}
+
+
+
+#endif // COMPILER2