1 /*
   2  * Copyright (c) 1999, 2010, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
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  24 
  25 #ifndef SHARE_VM_CI_CICALLPROFILE_HPP
  26 #define SHARE_VM_CI_CICALLPROFILE_HPP
  27 
  28 #include "ci/ciClassList.hpp"
  29 #include "memory/allocation.hpp"
  30 
  31 // ciCallProfile
  32 //
  33 // This class is used to determine the frequently called method
  34 // at some call site
  35 class ciCallProfile : StackObj {
  36 private:
  37   // Fields are initialized directly by ciMethod::call_profile_at_bci.
  38   friend class ciMethod;
  39   friend class ciMethodHandle;
  40 
  41   enum { MorphismLimit = 2 }; // Max call site's morphism we care about
  42   int  _limit;                // number of receivers have been determined
  43   int  _morphism;             // determined call site's morphism
  44   int  _count;                // # times has this call been executed
  45   int  _receiver_count[MorphismLimit + 1]; // # times receivers have been seen
  46   ciMethod* _method[MorphismLimit + 1];    // receivers methods
  47   ciKlass*  _receiver[MorphismLimit + 1];  // receivers (exact)
  48 
  49   ciCallProfile() {
  50     _limit = 0;
  51     _morphism    = 0;
  52     _count = -1;
  53     _receiver_count[0] = -1;
  54     _method[0]   = NULL;
  55     _receiver[0] = NULL;
  56   }
  57 
  58   void add_receiver(ciKlass* receiver, int receiver_count);
  59 
  60 public:
  61   // Note:  The following predicates return false for invalid profiles:
  62   bool      has_receiver(int i) const { return _limit > i; }
  63   int       morphism() const          { return _morphism; }
  64 
  65   int       count() const             { return _count; }
  66   int       receiver_count(int i)  {
  67     assert(i < _limit, "out of Call Profile MorphismLimit");
  68     return _receiver_count[i];
  69   }
  70   float     receiver_prob(int i)  {
  71     assert(i < _limit, "out of Call Profile MorphismLimit");
  72     return (float)_receiver_count[i]/(float)_count;
  73   }
  74   ciMethod* method(int i)          {
  75     assert(i < _limit, "out of Call Profile MorphismLimit");
  76     return _method[i];
  77   }
  78   ciKlass*  receiver(int i)        {
  79     assert(i < _limit, "out of Call Profile MorphismLimit");
  80     return _receiver[i];
  81   }
  82 
  83   // Rescale the current profile based on the incoming scale
  84   ciCallProfile rescale(double scale) {
  85     assert(scale >= 0 && scale <= 1.0, "out of range");
  86     ciCallProfile call = *this;
  87     call._count = (int)(call._count * scale);
  88     for (int i = 0; i < _morphism; i++) {
  89       call._receiver_count[i] = (int)(call._receiver_count[i] * scale);
  90     }
  91     return call;
  92   }
  93 };
  94 
  95 #endif // SHARE_VM_CI_CICALLPROFILE_HPP