/*

 * Copyright 2000-2010 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() && CompileBroker::should_compile_new_jobs()); // 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;

  // 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;

  }

  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 && CompileBroker::should_compile_new_jobs()) {

    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::should_compile_new_jobs()) {

    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 && CompileBroker::should_compile_new_jobs()) {

    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::should_compile_new_jobs()) {

    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