1 /*
   2  * Copyright 2000-2005 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
  20  * CA 95054 USA or visit www.sun.com if you need additional information or
  21  * have any questions.
  22  *
  23  */
  24 
  25 //---------------------------CallGenerator-------------------------------------
  26 // The subclasses of this class handle generation of ideal nodes for
  27 // call sites and method entry points.
  28 
  29 class CallGenerator : public ResourceObj {
  30  public:
  31   enum {
  32     xxxunusedxxx
  33   };
  34 
  35  private:
  36   ciMethod*             _method;                // The method being called.
  37 
  38  protected:
  39   CallGenerator(ciMethod* method);
  40 
  41  public:
  42   // Accessors
  43   ciMethod*         method() const              { return _method; }
  44 
  45   // is_inline: At least some code implementing the method is copied here.
  46   virtual bool      is_inline() const           { return false; }
  47   // is_intrinsic: There's a method-specific way of generating the inline code.
  48   virtual bool      is_intrinsic() const        { return false; }
  49   // is_parse: Bytecodes implementing the specific method are copied here.
  50   virtual bool      is_parse() const            { return false; }
  51   // is_virtual: The call uses the receiver type to select or check the method.
  52   virtual bool      is_virtual() const          { return false; }
  53   // is_deferred: The decision whether to inline or not is deferred.
  54   virtual bool      is_deferred() const         { return false; }
  55   // is_predicted: Uses an explicit check against a predicted type.
  56   virtual bool      is_predicted() const        { return false; }
  57   // is_trap: Does not return to the caller.  (E.g., uncommon trap.)
  58   virtual bool      is_trap() const             { return false; }
  59 
  60   // is_late_inline: supports conversion of call into an inline
  61   virtual bool      is_late_inline() const      { return false; }
  62   // Replace the call with an inline version of the code
  63   virtual void do_late_inline() { ShouldNotReachHere(); }
  64 
  65   virtual CallStaticJavaNode* call_node() const { ShouldNotReachHere(); return NULL; }
  66 
  67   // Note:  It is possible for a CG to be both inline and virtual.
  68   // (The hashCode intrinsic does a vtable check and an inlined fast path.)
  69 
  70   // Utilities:
  71   const TypeFunc*   tf() const;
  72 
  73   // The given jvms has state and arguments for a call to my method.
  74   // Edges after jvms->argoff() carry all (pre-popped) argument values.
  75   //
  76   // Update the map with state and return values (if any) and return it.
  77   // The return values (0, 1, or 2) must be pushed on the map's stack,
  78   // and the sp of the jvms incremented accordingly.
  79   //
  80   // The jvms is returned on success.  Alternatively, a copy of the
  81   // given jvms, suitably updated, may be returned, in which case the
  82   // caller should discard the original jvms.
  83   //
  84   // The non-Parm edges of the returned map will contain updated global state,
  85   // and one or two edges before jvms->sp() will carry any return values.
  86   // Other map edges may contain locals or monitors, and should not
  87   // be changed in meaning.
  88   //
  89   // If the call traps, the returned map must have a control edge of top.
  90   // If the call can throw, the returned map must report has_exceptions().
  91   //
  92   // If the result is NULL, it means that this CallGenerator was unable
  93   // to handle the given call, and another CallGenerator should be consulted.
  94   virtual JVMState* generate(JVMState* jvms) = 0;
  95 
  96   // How to generate a call site that is inlined:
  97   static CallGenerator* for_inline(ciMethod* m, float expected_uses = -1);
  98   // How to generate code for an on-stack replacement handler.
  99   static CallGenerator* for_osr(ciMethod* m, int osr_bci);
 100 
 101   // How to generate vanilla out-of-line call sites:
 102   static CallGenerator* for_direct_call(ciMethod* m, bool separate_io_projs = false);   // static, special
 103   static CallGenerator* for_virtual_call(ciMethod* m, int vtable_index);  // virtual, interface
 104 
 105   // How to generate a replace a direct call with an inline version
 106   static CallGenerator* for_late_inline(ciMethod* m, CallGenerator* inline_cg);
 107 
 108   // How to make a call but defer the decision whether to inline or not.
 109   static CallGenerator* for_warm_call(WarmCallInfo* ci,
 110                                       CallGenerator* if_cold,
 111                                       CallGenerator* if_hot);
 112 
 113   // How to make a call that optimistically assumes a receiver type:
 114   static CallGenerator* for_predicted_call(ciKlass* predicted_receiver,
 115                                            CallGenerator* if_missed,
 116                                            CallGenerator* if_hit,
 117                                            float hit_prob);
 118 
 119   // How to make a call that gives up and goes back to the interpreter:
 120   static CallGenerator* for_uncommon_trap(ciMethod* m,
 121                                           Deoptimization::DeoptReason reason,
 122                                           Deoptimization::DeoptAction action);
 123 
 124   // Registry for intrinsics:
 125   static CallGenerator* for_intrinsic(ciMethod* m);
 126   static void register_intrinsic(ciMethod* m, CallGenerator* cg);
 127 };
 128 
 129 class InlineCallGenerator : public CallGenerator {
 130   virtual bool      is_inline() const           { return true; }
 131 
 132  protected:
 133   InlineCallGenerator(ciMethod* method) : CallGenerator(method) { }
 134 };
 135 
 136 
 137 //---------------------------WarmCallInfo--------------------------------------
 138 // A struct to collect information about a given call site.
 139 // Helps sort call sites into "hot", "medium", and "cold".
 140 // Participates in the queueing of "medium" call sites for possible inlining.
 141 class WarmCallInfo : public ResourceObj {
 142  private:
 143 
 144   CallNode*     _call;   // The CallNode which may be inlined.
 145   CallGenerator* _hot_cg;// CG for expanding the call node
 146 
 147   // These are the metrics we use to evaluate call sites:
 148 
 149   float         _count;  // How often do we expect to reach this site?
 150   float         _profit; // How much time do we expect to save by inlining?
 151   float         _work;   // How long do we expect the average call to take?
 152   float         _size;   // How big do we expect the inlined code to be?
 153 
 154   float         _heat;   // Combined score inducing total order on call sites.
 155   WarmCallInfo* _next;   // Next cooler call info in pending queue.
 156 
 157   // Count is the number of times this call site is expected to be executed.
 158   // Large count is favorable for inlining, because the extra compilation
 159   // work will be amortized more completely.
 160 
 161   // Profit is a rough measure of the amount of time we expect to save
 162   // per execution of this site if we inline it.  (1.0 == call overhead)
 163   // Large profit favors inlining.  Negative profit disables inlining.
 164 
 165   // Work is a rough measure of the amount of time a typical out-of-line
 166   // call from this site is expected to take.  (1.0 == call, no-op, return)
 167   // Small work is somewhat favorable for inlining, since methods with
 168   // short "hot" traces are more likely to inline smoothly.
 169 
 170   // Size is the number of graph nodes we expect this method to produce,
 171   // not counting the inlining of any further warm calls it may include.
 172   // Small size favors inlining, since small methods are more likely to
 173   // inline smoothly.  The size is estimated by examining the native code
 174   // if available.  The method bytecodes are also examined, assuming
 175   // empirically observed node counts for each kind of bytecode.
 176 
 177   // Heat is the combined "goodness" of a site's inlining.  If we were
 178   // omniscient, it would be the difference of two sums of future execution
 179   // times of code emitted for this site (amortized across multiple sites if
 180   // sharing applies).  The two sums are for versions of this call site with
 181   // and without inlining.
 182 
 183   // We approximate this mythical quantity by playing with averages,
 184   // rough estimates, and assumptions that history repeats itself.
 185   // The basic formula count * profit is heuristically adjusted
 186   // by looking at the expected compilation and execution times of
 187   // of the inlined call.
 188 
 189   // Note:  Some of these metrics may not be present in the final product,
 190   // but exist in development builds to experiment with inline policy tuning.
 191 
 192   // This heuristic framework does not model well the very significant
 193   // effects of multiple-level inlining.  It is possible to see no immediate
 194   // profit from inlining X->Y, but to get great profit from a subsequent
 195   // inlining X->Y->Z.
 196 
 197   // This framework does not take well into account the problem of N**2 code
 198   // size in a clique of mutually inlinable methods.
 199 
 200   WarmCallInfo*  next() const          { return _next; }
 201   void       set_next(WarmCallInfo* n) { _next = n; }
 202 
 203   static WarmCallInfo* _always_hot;
 204   static WarmCallInfo* _always_cold;
 205 
 206  public:
 207   // Because WarmInfo objects live over the entire lifetime of the
 208   // Compile object, they are allocated into the comp_arena, which
 209   // does not get resource marked or reset during the compile process
 210   void *operator new( size_t x, Compile* C ) { return C->comp_arena()->Amalloc(x); }
 211   void operator delete( void * ) { } // fast deallocation
 212 
 213   static WarmCallInfo* always_hot();
 214   static WarmCallInfo* always_cold();
 215 
 216   WarmCallInfo() {
 217     _call = NULL;
 218     _hot_cg = NULL;
 219     _next = NULL;
 220     _count = _profit = _work = _size = _heat = 0;
 221   }
 222 
 223   CallNode* call() const { return _call; }
 224   float count()    const { return _count; }
 225   float size()     const { return _size; }
 226   float work()     const { return _work; }
 227   float profit()   const { return _profit; }
 228   float heat()     const { return _heat; }
 229 
 230   void set_count(float x)     { _count = x; }
 231   void set_size(float x)      { _size = x; }
 232   void set_work(float x)      { _work = x; }
 233   void set_profit(float x)    { _profit = x; }
 234   void set_heat(float x)      { _heat = x; }
 235 
 236   // Load initial heuristics from profiles, etc.
 237   // The heuristics can be tweaked further by the caller.
 238   void init(JVMState* call_site, ciMethod* call_method, ciCallProfile& profile, float prof_factor);
 239 
 240   static float MAX_VALUE() { return +1.0e10; }
 241   static float MIN_VALUE() { return -1.0e10; }
 242 
 243   float compute_heat() const;
 244 
 245   void set_call(CallNode* call)      { _call = call; }
 246   void set_hot_cg(CallGenerator* cg) { _hot_cg = cg; }
 247 
 248   // Do not queue very hot or very cold calls.
 249   // Make very cold ones out of line immediately.
 250   // Inline very hot ones immediately.
 251   // These queries apply various tunable limits
 252   // to the above metrics in a systematic way.
 253   // Test for coldness before testing for hotness.
 254   bool is_cold() const;
 255   bool is_hot() const;
 256 
 257   // Force a warm call to be hot.  This worklists the call node for inlining.
 258   void make_hot();
 259 
 260   // Force a warm call to be cold.  This worklists the call node for out-of-lining.
 261   void make_cold();
 262 
 263   // A reproducible total ordering, in which heat is the major key.
 264   bool warmer_than(WarmCallInfo* that);
 265 
 266   // List management.  These methods are called with the list head,
 267   // and return the new list head, inserting or removing the receiver.
 268   WarmCallInfo* insert_into(WarmCallInfo* head);
 269   WarmCallInfo* remove_from(WarmCallInfo* head);
 270 
 271 #ifndef PRODUCT
 272   void print() const;
 273   void print_all() const;
 274   int count_all() const;
 275 #endif
 276 };