Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright 2000-2005 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.

  *

  */

 //---------------------------CallGenerator-------------------------------------

 // The subclasses of this class handle generation of ideal nodes for

 // call sites and method entry points.

 class CallGenerator : public ResourceObj {

  public:

   enum {

     xxxunusedxxx

   };

  private:

   ciMethod*             _method;                // The method being called.

  protected:

   CallGenerator(ciMethod* method);

  public:

   // Accessors

   ciMethod*         method() const              { return _method; }

   // is_inline: At least some code implementing the method is copied here.

   virtual bool      is_inline() const           { return false; }

   // is_intrinsic: There's a method-specific way of generating the inline code.

   virtual bool      is_intrinsic() const        { return false; }

   // is_parse: Bytecodes implementing the specific method are copied here.

   virtual bool      is_parse() const            { return false; }

   // is_virtual: The call uses the receiver type to select or check the method.

   virtual bool      is_virtual() const          { return false; }

   // is_deferred: The decision whether to inline or not is deferred.

   virtual bool      is_deferred() const         { return false; }

   // is_predicted: Uses an explicit check against a predicted type.

   virtual bool      is_predicted() const        { return false; }

   // is_trap: Does not return to the caller.  (E.g., uncommon trap.)

   virtual bool      is_trap() const             { return false; }

   // Note:  It is possible for a CG to be both inline and virtual.

   // (The hashCode intrinsic does a vtable check and an inlined fast path.)

   // Utilities:

   const TypeFunc*   tf() const;

   // The given jvms has state and arguments for a call to my method.

   // Edges after jvms->argoff() carry all (pre-popped) argument values.

   //

   // Update the map with state and return values (if any) and return it.

   // The return values (0, 1, or 2) must be pushed on the map's stack,

   // and the sp of the jvms incremented accordingly.

   //

   // The jvms is returned on success.  Alternatively, a copy of the

   // given jvms, suitably updated, may be returned, in which case the

   // caller should discard the original jvms.

   //

   // The non-Parm edges of the returned map will contain updated global state,

   // and one or two edges before jvms->sp() will carry any return values.

   // Other map edges may contain locals or monitors, and should not

   // be changed in meaning.

   //

   // If the call traps, the returned map must have a control edge of top.

   // If the call can throw, the returned map must report has_exceptions().

   //

   // If the result is NULL, it means that this CallGenerator was unable

   // to handle the given call, and another CallGenerator should be consulted.

   virtual JVMState* generate(JVMState* jvms) = 0;

   // How to generate a call site that is inlined:

   static CallGenerator* for_inline(ciMethod* m, float expected_uses = -1);

   // How to generate code for an on-stack replacement handler.

   static CallGenerator* for_osr(ciMethod* m, int osr_bci);

   // How to generate vanilla out-of-line call sites:

   static CallGenerator* for_direct_call(ciMethod* m);   // static, special

   static CallGenerator* for_virtual_call(ciMethod* m, int vtable_index);  // virtual, interface

   // How to make a call but defer the decision whether to inline or not.

   static CallGenerator* for_warm_call(WarmCallInfo* ci,

                                       CallGenerator* if_cold,

                                       CallGenerator* if_hot);

   // How to make a call that optimistically assumes a receiver type:

   static CallGenerator* for_predicted_call(ciKlass* predicted_receiver,

                                            CallGenerator* if_missed,

                                            CallGenerator* if_hit,

                                            float hit_prob);

   // How to make a call that gives up and goes back to the interpreter:

   static CallGenerator* for_uncommon_trap(ciMethod* m,

                                           Deoptimization::DeoptReason reason,

                                           Deoptimization::DeoptAction action);

   // Registry for intrinsics:

   static CallGenerator* for_intrinsic(ciMethod* m);

   static void register_intrinsic(ciMethod* m, CallGenerator* cg);

 };

 class InlineCallGenerator : public CallGenerator {

   virtual bool      is_inline() const           { return true; }

  protected:

   InlineCallGenerator(ciMethod* method) : CallGenerator(method) { }

 };

 //---------------------------WarmCallInfo--------------------------------------

 // A struct to collect information about a given call site.

 // Helps sort call sites into "hot", "medium", and "cold".

 // Participates in the queueing of "medium" call sites for possible inlining.

 class WarmCallInfo : public ResourceObj {

  private:

   CallNode*     _call;   // The CallNode which may be inlined.

   CallGenerator* _hot_cg;// CG for expanding the call node

   // These are the metrics we use to evaluate call sites:

   float         _count;  // How often do we expect to reach this site?

   float         _profit; // How much time do we expect to save by inlining?

   float         _work;   // How long do we expect the average call to take?

   float         _size;   // How big do we expect the inlined code to be?

   float         _heat;   // Combined score inducing total order on call sites.

   WarmCallInfo* _next;   // Next cooler call info in pending queue.

   // Count is the number of times this call site is expected to be executed.

   // Large count is favorable for inlining, because the extra compilation

   // work will be amortized more completely.

   // Profit is a rough measure of the amount of time we expect to save

   // per execution of this site if we inline it.  (1.0 == call overhead)

   // Large profit favors inlining.  Negative profit disables inlining.

   // Work is a rough measure of the amount of time a typical out-of-line

   // call from this site is expected to take.  (1.0 == call, no-op, return)

   // Small work is somewhat favorable for inlining, since methods with

   // short "hot" traces are more likely to inline smoothly.

   // Size is the number of graph nodes we expect this method to produce,

   // not counting the inlining of any further warm calls it may include.

   // Small size favors inlining, since small methods are more likely to

   // inline smoothly.  The size is estimated by examining the native code

   // if available.  The method bytecodes are also examined, assuming

   // empirically observed node counts for each kind of bytecode.

   // Heat is the combined "goodness" of a site's inlining.  If we were

   // omniscient, it would be the difference of two sums of future execution

   // times of code emitted for this site (amortized across multiple sites if

   // sharing applies).  The two sums are for versions of this call site with

   // and without inlining.

   // We approximate this mythical quantity by playing with averages,

   // rough estimates, and assumptions that history repeats itself.

   // The basic formula count * profit is heuristically adjusted

   // by looking at the expected compilation and execution times of

   // of the inlined call.

   // Note:  Some of these metrics may not be present in the final product,

   // but exist in development builds to experiment with inline policy tuning.

   // This heuristic framework does not model well the very significant

   // effects of multiple-level inlining.  It is possible to see no immediate

   // profit from inlining X->Y, but to get great profit from a subsequent

   // inlining X->Y->Z.

   // This framework does not take well into account the problem of N**2 code

   // size in a clique of mutually inlinable methods.

   WarmCallInfo*  next() const          { return _next; }

   void       set_next(WarmCallInfo* n) { _next = n; }

   static WarmCallInfo* _always_hot;

   static WarmCallInfo* _always_cold;

  public:

   // Because WarmInfo objects live over the entire lifetime of the

   // Compile object, they are allocated into the comp_arena, which

   // does not get resource marked or reset during the compile process

   void *operator new( size_t x, Compile* C ) { return C->comp_arena()->Amalloc(x); }

   void operator delete( void * ) { } // fast deallocation

   static WarmCallInfo* always_hot();

   static WarmCallInfo* always_cold();

   WarmCallInfo() {

     _call = NULL;

     _hot_cg = NULL;

     _next = NULL;

     _count = _profit = _work = _size = _heat = 0;

   }

   CallNode* call() const { return _call; }

   float count()    const { return _count; }

   float size()     const { return _size; }

   float work()     const { return _work; }

   float profit()   const { return _profit; }

   float heat()     const { return _heat; }

   void set_count(float x)     { _count = x; }

   void set_size(float x)      { _size = x; }

   void set_work(float x)      { _work = x; }

   void set_profit(float x)    { _profit = x; }

   void set_heat(float x)      { _heat = x; }

   // Load initial heuristics from profiles, etc.

   // The heuristics can be tweaked further by the caller.

   void init(JVMState* call_site, ciMethod* call_method, ciCallProfile& profile, float prof_factor);

   static float MAX_VALUE() { return +1.0e10; }

   static float MIN_VALUE() { return -1.0e10; }

   float compute_heat() const;

   void set_call(CallNode* call)      { _call = call; }

   void set_hot_cg(CallGenerator* cg) { _hot_cg = cg; }

   // Do not queue very hot or very cold calls.

   // Make very cold ones out of line immediately.

   // Inline very hot ones immediately.

   // These queries apply various tunable limits

   // to the above metrics in a systematic way.

   // Test for coldness before testing for hotness.

   bool is_cold() const;

   bool is_hot() const;

   // Force a warm call to be hot.  This worklists the call node for inlining.

   void make_hot();

   // Force a warm call to be cold.  This worklists the call node for out-of-lining.

   void make_cold();

   // A reproducible total ordering, in which heat is the major key.

   bool warmer_than(WarmCallInfo* that);

   // List management.  These methods are called with the list head,

   // and return the new list head, inserting or removing the receiver.

   WarmCallInfo* insert_into(WarmCallInfo* head);

   WarmCallInfo* remove_from(WarmCallInfo* head);

 #ifndef PRODUCT

   void print() const;

   void print_all() const;

   int count_all() const;

 #endif

 };