/javac_compiler/HotspotSource/JavaHotSpotSrc/src/vm/opto/bytecodeInfo.cpp

/*

 * Copyright (c) 1998, 2010, 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 "incls/_precompiled.incl"

#include "incls/_bytecodeInfo.cpp.incl"



//=============================================================================

//------------------------------InlineTree-------------------------------------

InlineTree::InlineTree( Compile* c,

                        const InlineTree *caller_tree, ciMethod* callee,

                        JVMState* caller_jvms, int caller_bci,

                        float site_invoke_ratio, int site_depth_adjust)

: C(c), _caller_jvms(caller_jvms),

  _caller_tree((InlineTree*)caller_tree),

  _method(callee), _site_invoke_ratio(site_invoke_ratio),

  _site_depth_adjust(site_depth_adjust),

  _count_inline_bcs(method()->code_size())

{

  NOT_PRODUCT(_count_inlines = 0;)

  if (_caller_jvms != NULL) {

    // Keep a private copy of the caller_jvms:

    _caller_jvms = new (C) JVMState(caller_jvms->method(), caller_tree->caller_jvms());

    _caller_jvms->set_bci(caller_jvms->bci());

    assert(!caller_jvms->should_reexecute(), "there should be no reexecute bytecode with inlining");

  }

  assert(_caller_jvms->same_calls_as(caller_jvms), "consistent JVMS");

  assert((caller_tree == NULL ? 0 : caller_tree->stack_depth() + 1) == stack_depth(), "correct (redundant) depth parameter");

  assert(caller_bci == this->caller_bci(), "correct (redundant) bci parameter");

  if (UseOldInlining) {

    // Update hierarchical counts, count_inline_bcs() and count_inlines()

    InlineTree *caller = (InlineTree *)caller_tree;

    for( ; caller != NULL; caller = ((InlineTree *)(caller->caller_tree())) ) {

      caller->_count_inline_bcs += count_inline_bcs();

      NOT_PRODUCT(caller->_count_inlines++;)

    }

  }

}



InlineTree::InlineTree(Compile* c, ciMethod* callee_method, JVMState* caller_jvms,

                       float site_invoke_ratio, int site_depth_adjust)

: C(c), _caller_jvms(caller_jvms), _caller_tree(NULL),

  _method(callee_method), _site_invoke_ratio(site_invoke_ratio),

  _site_depth_adjust(site_depth_adjust),

  _count_inline_bcs(method()->code_size())

{

  NOT_PRODUCT(_count_inlines = 0;)

  assert(!UseOldInlining, "do not use for old stuff");

}







static void print_indent(int depth) {

  tty->print("      ");

  for (int i = depth; i != 0; --i) tty->print("  ");

}



static bool is_init_with_ea(ciMethod* callee_method,

                            ciMethod* caller_method, Compile* C) {

  // True when EA is ON and a java constructor is called or

  // a super constructor is called from an inlined java constructor.

  return C->do_escape_analysis() && EliminateAllocations &&

         ( callee_method->is_initializer() ||

           (caller_method->is_initializer() &&

            caller_method != C->method() &&

            caller_method->holder()->is_subclass_of(callee_method->holder()))

         );

}



// positive filter: should send be inlined?  returns NULL, if yes, or rejection msg

const char* InlineTree::shouldInline(ciMethod* callee_method, ciMethod* caller_method, int caller_bci, ciCallProfile& profile, WarmCallInfo* wci_result) const {

  // Allows targeted inlining

  if(callee_method->should_inline()) {

    *wci_result = *(WarmCallInfo::always_hot());

    if (PrintInlining && Verbose) {

      print_indent(inline_depth());

      tty->print_cr("Inlined method is hot: ");

    }

    return NULL;

  }



  // positive filter: should send be inlined?  returns NULL (--> yes)

  // or rejection msg

  int max_size = C->max_inline_size();

  int size     = callee_method->code_size();



  // Check for too many throws (and not too huge)

  if(callee_method->interpreter_throwout_count() > InlineThrowCount &&

     size < InlineThrowMaxSize ) {

    wci_result->set_profit(wci_result->profit() * 100);

    if (PrintInlining && Verbose) {

      print_indent(inline_depth());

      tty->print_cr("Inlined method with many throws (throws=%d):", callee_method->interpreter_throwout_count());

    }

    return NULL;

  }



  if (!UseOldInlining) {

    return NULL;  // size and frequency are represented in a new way

  }



  int call_site_count  = method()->scale_count(profile.count());

  int invoke_count     = method()->interpreter_invocation_count();

  assert( invoke_count != 0, "Require invokation count greater than zero");

  int freq = call_site_count/invoke_count;



  // bump the max size if the call is frequent

  if ((freq >= InlineFrequencyRatio) ||

      (call_site_count >= InlineFrequencyCount) ||

      is_init_with_ea(callee_method, caller_method, C)) {



    max_size = C->freq_inline_size();

    if (size <= max_size && TraceFrequencyInlining) {

      print_indent(inline_depth());

      tty->print_cr("Inlined frequent method (freq=%d count=%d):", freq, call_site_count);

      print_indent(inline_depth());

      callee_method->print();

      tty->cr();

    }

  } else {

    // Not hot.  Check for medium-sized pre-existing nmethod at cold sites.

    if (callee_method->has_compiled_code() &&

        callee_method->instructions_size() > InlineSmallCode/4)

      return "already compiled into a medium method";

  }

  if (size > max_size) {

    if (max_size > C->max_inline_size())

      return "hot method too big";

    return "too big";

  }

  return NULL;

}





// negative filter: should send NOT be inlined?  returns NULL, ok to inline, or rejection msg

const char* InlineTree::shouldNotInline(ciMethod *callee_method, ciMethod* caller_method, WarmCallInfo* wci_result) const {

  // negative filter: should send NOT be inlined?  returns NULL (--> inline) or rejection msg

  if (!UseOldInlining) {

    const char* fail = NULL;

    if (callee_method->is_abstract())               fail = "abstract method";

    // note: we allow ik->is_abstract()

    if (!callee_method->holder()->is_initialized()) fail = "method holder not initialized";

    if (callee_method->is_native())                 fail = "native method";



    if (fail) {

      *wci_result = *(WarmCallInfo::always_cold());

      return fail;

    }



    if (callee_method->has_unloaded_classes_in_signature()) {

      wci_result->set_profit(wci_result->profit() * 0.1);

    }



    // don't inline exception code unless the top method belongs to an

    // exception class

    if (callee_method->holder()->is_subclass_of(C->env()->Throwable_klass())) {

      ciMethod* top_method = caller_jvms() ? caller_jvms()->of_depth(1)->method() : method();

      if (!top_method->holder()->is_subclass_of(C->env()->Throwable_klass())) {

        wci_result->set_profit(wci_result->profit() * 0.1);

      }

    }



    if (callee_method->has_compiled_code() && callee_method->instructions_size() > InlineSmallCode) {

      wci_result->set_profit(wci_result->profit() * 0.1);

      // %%% adjust wci_result->size()?

    }



    return NULL;

  }



  // Always inline MethodHandle methods and generated MethodHandle adapters.

  if (callee_method->is_method_handle_invoke() || callee_method->is_method_handle_adapter())

    return NULL;



  // First check all inlining restrictions which are required for correctness

  if (callee_method->is_abstract())               return "abstract method";

  // note: we allow ik->is_abstract()

  if (!callee_method->holder()->is_initialized()) return "method holder not initialized";

  if (callee_method->is_native())                 return "native method";

  if (callee_method->has_unloaded_classes_in_signature()) return "unloaded signature classes";



  if (callee_method->should_inline()) {

    // ignore heuristic controls on inlining

    return NULL;

  }



  // Now perform checks which are heuristic



  if( callee_method->has_compiled_code() && callee_method->instructions_size() > InlineSmallCode )

    return "already compiled into a big method";



  // don't inline exception code unless the top method belongs to an

  // exception class

  if (caller_tree() != NULL &&

      callee_method->holder()->is_subclass_of(C->env()->Throwable_klass())) {

    const InlineTree *top = this;

    while (top->caller_tree() != NULL) top = top->caller_tree();

    ciInstanceKlass* k = top->method()->holder();

    if (!k->is_subclass_of(C->env()->Throwable_klass()))

      return "exception method";

  }



  // use frequency-based objections only for non-trivial methods

  if (callee_method->code_size() <= MaxTrivialSize) return NULL;



  // don't use counts with -Xcomp or CTW

  if (UseInterpreter && !CompileTheWorld) {



    if (!callee_method->has_compiled_code() &&

        !callee_method->was_executed_more_than(0)) {

      return "never executed";

    }



    if (is_init_with_ea(callee_method, caller_method, C)) {



      // Escape Analysis: inline all executed constructors



    } else if (!callee_method->was_executed_more_than(MIN2(MinInliningThreshold,

                                                           CompileThreshold >> 1))) {

      return "executed < MinInliningThreshold times";

    }

  }



  if (callee_method->should_not_inline()) {

    return "disallowed by CompilerOracle";

  }



  if (UseStringCache) {

    // Do not inline StringCache::profile() method used only at the beginning.

    if (callee_method->name() == ciSymbol::profile_name() &&

        callee_method->holder()->name() == ciSymbol::java_lang_StringCache()) {

      return "profiling method";

    }

  }



  return NULL;

}



//-----------------------------try_to_inline-----------------------------------

// return NULL if ok, reason for not inlining otherwise

// Relocated from "InliningClosure::try_to_inline"

const char* InlineTree::try_to_inline(ciMethod* callee_method, ciMethod* caller_method, int caller_bci, ciCallProfile& profile, WarmCallInfo* wci_result) {



  // Old algorithm had funny accumulating BC-size counters

  if (UseOldInlining && ClipInlining

      && (int)count_inline_bcs() >= DesiredMethodLimit) {

    return "size > DesiredMethodLimit";

  }



  const char *msg = NULL;

  if ((msg = shouldInline(callee_method, caller_method, caller_bci,

                          profile, wci_result)) != NULL) {

    return msg;

  }

  if ((msg = shouldNotInline(callee_method, caller_method,

                             wci_result)) != NULL) {

    return msg;

  }



  if (InlineAccessors && callee_method->is_accessor()) {

    // accessor methods are not subject to any of the following limits.

    return NULL;

  }



  // suppress a few checks for accessors and trivial methods

  if (callee_method->code_size() > MaxTrivialSize) {



    // don't inline into giant methods

    if (C->unique() > (uint)NodeCountInliningCutoff) {

      return "NodeCountInliningCutoff";

    }



    if ((!UseInterpreter || CompileTheWorld) &&

        is_init_with_ea(callee_method, caller_method, C)) {



      // Escape Analysis stress testing when running Xcomp or CTW:

      // inline constructors even if they are not reached.



    } else if (profile.count() == 0) {

      // don't inline unreached call sites

      return "call site not reached";

    }

  }



  if (!C->do_inlining() && InlineAccessors) {

    return "not an accessor";

  }

  if( inline_depth() > MaxInlineLevel ) {

    return "inlining too deep";

  }

  if( method() == callee_method &&

      inline_depth() > MaxRecursiveInlineLevel ) {

    return "recursively inlining too deep";

  }



  int size = callee_method->code_size();



  if (UseOldInlining && ClipInlining

      && (int)count_inline_bcs() + size >= DesiredMethodLimit) {

    return "size > DesiredMethodLimit";

  }



  // ok, inline this method

  return NULL;

}



//------------------------------pass_initial_checks----------------------------

bool pass_initial_checks(ciMethod* caller_method, int caller_bci, ciMethod* callee_method) {

  ciInstanceKlass *callee_holder = callee_method ? callee_method->holder() : NULL;

  // Check if a callee_method was suggested

  if( callee_method == NULL )            return false;

  // Check if klass of callee_method is loaded

  if( !callee_holder->is_loaded() )      return false;

  if( !callee_holder->is_initialized() ) return false;

  if( !UseInterpreter || CompileTheWorld /* running Xcomp or CTW */ ) {

    // Checks that constant pool's call site has been visited

    // stricter than callee_holder->is_initialized()

    ciBytecodeStream iter(caller_method);

    iter.force_bci(caller_bci);

    Bytecodes::Code call_bc = iter.cur_bc();

    // An invokedynamic instruction does not have a klass.

    if (call_bc != Bytecodes::_invokedynamic) {

      int index = iter.get_index_u2_cpcache();

      if (!caller_method->is_klass_loaded(index, true)) {

        return false;

      }

      // Try to do constant pool resolution if running Xcomp

      if( !caller_method->check_call(index, call_bc == Bytecodes::_invokestatic) ) {

        return false;

      }

    }

  }

  // We will attempt to see if a class/field/etc got properly loaded.  If it

  // did not, it may attempt to throw an exception during our probing.  Catch

  // and ignore such exceptions and do not attempt to compile the method.

  if( callee_method->should_exclude() )  return false;



  return true;

}



#ifndef PRODUCT

//------------------------------print_inlining---------------------------------

// Really, the failure_msg can be a success message also.

void InlineTree::print_inlining(ciMethod *callee_method, int caller_bci, const char *failure_msg) const {

  print_indent(inline_depth());

  tty->print("@ %d  ", caller_bci);

  if( callee_method ) callee_method->print_short_name();

  else                tty->print(" callee not monotonic or profiled");

  tty->print("  %s", (failure_msg ? failure_msg : "inline"));

  if( Verbose && callee_method ) {

    const InlineTree *top = this;

    while( top->caller_tree() != NULL ) { top = top->caller_tree(); }

    tty->print("  bcs: %d+%d  invoked: %d", top->count_inline_bcs(), callee_method->code_size(), callee_method->interpreter_invocation_count());

  }

  tty->cr();

}

#endif



//------------------------------ok_to_inline-----------------------------------

WarmCallInfo* InlineTree::ok_to_inline(ciMethod* callee_method, JVMState* jvms, ciCallProfile& profile, WarmCallInfo* initial_wci) {

  assert(callee_method != NULL, "caller checks for optimized virtual!");

#ifdef ASSERT

  // Make sure the incoming jvms has the same information content as me.

  // This means that we can eventually make this whole class AllStatic.

  if (jvms->caller() == NULL) {

    assert(_caller_jvms == NULL, "redundant instance state");

  } else {

    assert(_caller_jvms->same_calls_as(jvms->caller()), "redundant instance state");

  }

  assert(_method == jvms->method(), "redundant instance state");

#endif

  const char *failure_msg   = NULL;

  int         caller_bci    = jvms->bci();

  ciMethod   *caller_method = jvms->method();



  if( !pass_initial_checks(caller_method, caller_bci, callee_method)) {

    if( PrintInlining ) {

      failure_msg = "failed_initial_checks";

      print_inlining( callee_method, caller_bci, failure_msg);

    }

    return NULL;

  }



  // Check if inlining policy says no.

  WarmCallInfo wci = *(initial_wci);

  failure_msg = try_to_inline(callee_method, caller_method, caller_bci, profile, &wci);

  if (failure_msg != NULL && C->log() != NULL) {

    C->log()->begin_elem("inline_fail reason='");

    C->log()->text("%s", failure_msg);

    C->log()->end_elem("'");

  }



#ifndef PRODUCT

  if (UseOldInlining && InlineWarmCalls

      && (PrintOpto || PrintOptoInlining || PrintInlining)) {

    bool cold = wci.is_cold();

    bool hot  = !cold && wci.is_hot();

    bool old_cold = (failure_msg != NULL);

    if (old_cold != cold || (Verbose || WizardMode)) {

      tty->print("   OldInlining= %4s : %s\n           WCI=",

                 old_cold ? "cold" : "hot", failure_msg ? failure_msg : "OK");

      wci.print();

    }

  }

#endif

  if (UseOldInlining) {

    if (failure_msg == NULL)

      wci = *(WarmCallInfo::always_hot());

    else

      wci = *(WarmCallInfo::always_cold());

  }

  if (!InlineWarmCalls) {

    if (!wci.is_cold() && !wci.is_hot()) {

      // Do not inline the warm calls.

      wci = *(WarmCallInfo::always_cold());

    }

  }



  if (!wci.is_cold()) {

    // In -UseOldInlining, the failure_msg may also be a success message.

    if (failure_msg == NULL)  failure_msg = "inline (hot)";



    // Inline!

    if( PrintInlining ) print_inlining( callee_method, caller_bci, failure_msg);

    if (UseOldInlining)

      build_inline_tree_for_callee(callee_method, jvms, caller_bci);

    if (InlineWarmCalls && !wci.is_hot())

      return new (C) WarmCallInfo(wci);  // copy to heap

    return WarmCallInfo::always_hot();

  }



  // Do not inline

  if (failure_msg == NULL)  failure_msg = "too cold to inline";

  if( PrintInlining ) print_inlining( callee_method, caller_bci, failure_msg);

  return NULL;

}



//------------------------------compute_callee_frequency-----------------------

float InlineTree::compute_callee_frequency( int caller_bci ) const {

  int count  = method()->interpreter_call_site_count(caller_bci);

  int invcnt = method()->interpreter_invocation_count();

  float freq = (float)count/(float)invcnt;

  // Call-site count / interpreter invocation count, scaled recursively.

  // Always between 0.0 and 1.0.  Represents the percentage of the method's

  // total execution time used at this call site.



  return freq;

}



//------------------------------build_inline_tree_for_callee-------------------

InlineTree *InlineTree::build_inline_tree_for_callee( ciMethod* callee_method, JVMState* caller_jvms, int caller_bci) {

  float recur_frequency = _site_invoke_ratio * compute_callee_frequency(caller_bci);

  // Attempt inlining.

  InlineTree* old_ilt = callee_at(caller_bci, callee_method);

  if (old_ilt != NULL) {

    return old_ilt;

  }

  int new_depth_adjust = 0;

  if (caller_jvms->method() != NULL) {

    if (caller_jvms->method()->is_method_handle_adapter())

      new_depth_adjust -= 1;  // don't count actions in MH or indy adapter frames

    else if (callee_method->is_method_handle_invoke()) {

      new_depth_adjust -= 1;  // don't count method handle calls from java.dyn implem

    }

    if (new_depth_adjust != 0 && PrintInlining) {

      stringStream nm1; caller_jvms->method()->print_name(&nm1);

      stringStream nm2; callee_method->print_name(&nm2);

      tty->print_cr("discounting inlining depth from %s to %s", nm1.base(), nm2.base());

    }

    if (new_depth_adjust != 0 && C->log()) {

      int id1 = C->log()->identify(caller_jvms->method());

      int id2 = C->log()->identify(callee_method);

      C->log()->elem("inline_depth_discount caller='%d' callee='%d'", id1, id2);

    }

  }

  InlineTree *ilt = new InlineTree(C, this, callee_method, caller_jvms, caller_bci, recur_frequency, _site_depth_adjust + new_depth_adjust);

  _subtrees.append( ilt );



  NOT_PRODUCT( _count_inlines += 1; )



  return ilt;

}





//---------------------------------------callee_at-----------------------------

InlineTree *InlineTree::callee_at(int bci, ciMethod* callee) const {

  for (int i = 0; i < _subtrees.length(); i++) {

    InlineTree* sub = _subtrees.at(i);

    if (sub->caller_bci() == bci && callee == sub->method()) {

      return sub;

    }

  }

  return NULL;

}





//------------------------------build_inline_tree_root-------------------------

InlineTree *InlineTree::build_inline_tree_root() {

  Compile* C = Compile::current();



  // Root of inline tree

  InlineTree *ilt = new InlineTree(C, NULL, C->method(), NULL, -1, 1.0F, 0);



  return ilt;

}





//-------------------------find_subtree_from_root-----------------------------

// Given a jvms, which determines a call chain from the root method,

// find the corresponding inline tree.

// Note: This method will be removed or replaced as InlineTree goes away.

InlineTree* InlineTree::find_subtree_from_root(InlineTree* root, JVMState* jvms, ciMethod* callee, bool create_if_not_found) {

  InlineTree* iltp = root;

  uint depth = jvms && jvms->has_method() ? jvms->depth() : 0;

  for (uint d = 1; d <= depth; d++) {

    JVMState* jvmsp  = jvms->of_depth(d);

    // Select the corresponding subtree for this bci.

    assert(jvmsp->method() == iltp->method(), "tree still in sync");

    ciMethod* d_callee = (d == depth) ? callee : jvms->of_depth(d+1)->method();

    InlineTree* sub = iltp->callee_at(jvmsp->bci(), d_callee);

    if (!sub) {

      if (create_if_not_found && d == depth) {

        return iltp->build_inline_tree_for_callee(d_callee, jvmsp, jvmsp->bci());

      }

      assert(sub != NULL, "should be a sub-ilt here");

      return NULL;

    }

    iltp = sub;

  }

  return iltp;

}