1 /*
   2  * Copyright (c) 2000, 2012, 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
  21  * questions.
  22  *
  23  */
  24 
  25 #ifndef SHARE_VM_OPTO_CALLGENERATOR_HPP
  26 #define SHARE_VM_OPTO_CALLGENERATOR_HPP
  27 
  28 #include "compiler/compileBroker.hpp"
  29 #include "opto/callnode.hpp"
  30 #include "opto/compile.hpp"
  31 #include "opto/type.hpp"
  32 #include "runtime/deoptimization.hpp"
  33 
  34 //---------------------------CallGenerator-------------------------------------
  35 // The subclasses of this class handle generation of ideal nodes for
  36 // call sites and method entry points.
  37 
  38 class CallGenerator : public ResourceObj {
  39  public:
  40   enum {
  41     xxxunusedxxx
  42   };
  43 
  44  private:
  45   ciMethod*             _method;                // The method being called.
  46 
  47  protected:
  48   CallGenerator(ciMethod* method) : _method(method) {}
  49 
  50  public:
  51   // Accessors
  52   ciMethod*         method() const              { return _method; }
  53 
  54   // is_inline: At least some code implementing the method is copied here.
  55   virtual bool      is_inline() const           { return false; }
  56   // is_intrinsic: There's a method-specific way of generating the inline code.
  57   virtual bool      is_intrinsic() const        { return false; }
  58   // is_parse: Bytecodes implementing the specific method are copied here.
  59   virtual bool      is_parse() const            { return false; }
  60   // is_virtual: The call uses the receiver type to select or check the method.
  61   virtual bool      is_virtual() const          { return false; }
  62   // is_deferred: The decision whether to inline or not is deferred.
  63   virtual bool      is_deferred() const         { return false; }
  64   // is_predicted: Uses an explicit check against a predicted type.
  65   virtual bool      is_predicted() const        { return false; }
  66   // is_trap: Does not return to the caller.  (E.g., uncommon trap.)
  67   virtual bool      is_trap() const             { return false; }
  68 
  69   // is_late_inline: supports conversion of call into an inline
  70   virtual bool      is_late_inline() const      { return false; }
  71   // Replace the call with an inline version of the code
  72   virtual void do_late_inline() { ShouldNotReachHere(); }
  73 
  74   virtual CallStaticJavaNode* call_node() const { ShouldNotReachHere(); return NULL; }
  75 
  76   // Note:  It is possible for a CG to be both inline and virtual.
  77   // (The hashCode intrinsic does a vtable check and an inlined fast path.)
  78 
  79   // Utilities:
  80   const TypeFunc*   tf() const;
  81 
  82   // The given jvms has state and arguments for a call to my method.
  83   // Edges after jvms->argoff() carry all (pre-popped) argument values.
  84   //
  85   // Update the map with state and return values (if any) and return it.
  86   // The return values (0, 1, or 2) must be pushed on the map's stack,
  87   // and the sp of the jvms incremented accordingly.
  88   //
  89   // The jvms is returned on success.  Alternatively, a copy of the
  90   // given jvms, suitably updated, may be returned, in which case the
  91   // caller should discard the original jvms.
  92   //
  93   // The non-Parm edges of the returned map will contain updated global state,
  94   // and one or two edges before jvms->sp() will carry any return values.
  95   // Other map edges may contain locals or monitors, and should not
  96   // be changed in meaning.
  97   //
  98   // If the call traps, the returned map must have a control edge of top.
  99   // If the call can throw, the returned map must report has_exceptions().
 100   //
 101   // If the result is NULL, it means that this CallGenerator was unable
 102   // to handle the given call, and another CallGenerator should be consulted.
 103   virtual JVMState* generate(JVMState* jvms) = 0;
 104 
 105   // How to generate a call site that is inlined:
 106   static CallGenerator* for_inline(ciMethod* m, float expected_uses = -1);
 107   // How to generate code for an on-stack replacement handler.
 108   static CallGenerator* for_osr(ciMethod* m, int osr_bci);
 109 
 110   // How to generate vanilla out-of-line call sites:
 111   static CallGenerator* for_direct_call(ciMethod* m, bool separate_io_projs = false);   // static, special
 112   static CallGenerator* for_virtual_call(ciMethod* m, int vtable_index);  // virtual, interface
 113   static CallGenerator* for_dynamic_call(ciMethod* m);   // invokedynamic
 114 
 115   static CallGenerator* for_method_handle_call(  JVMState* jvms, ciMethod* caller, ciMethod* callee);
 116   static CallGenerator* for_method_handle_inline(JVMState* jvms, ciMethod* caller, ciMethod* callee);
 117 
 118   // How to generate a replace a direct call with an inline version
 119   static CallGenerator* for_late_inline(ciMethod* m, CallGenerator* inline_cg);
 120 
 121   // How to make a call but defer the decision whether to inline or not.
 122   static CallGenerator* for_warm_call(WarmCallInfo* ci,
 123                                       CallGenerator* if_cold,
 124                                       CallGenerator* if_hot);
 125 
 126   // How to make a call that optimistically assumes a receiver type:
 127   static CallGenerator* for_predicted_call(ciKlass* predicted_receiver,
 128                                            CallGenerator* if_missed,
 129                                            CallGenerator* if_hit,
 130                                            float hit_prob);
 131 
 132   // How to make a call that optimistically assumes a MethodHandle target:
 133   static CallGenerator* for_predicted_dynamic_call(ciMethodHandle* predicted_method_handle,
 134                                                    CallGenerator* if_missed,
 135                                                    CallGenerator* if_hit,
 136                                                    float hit_prob);
 137 
 138   // How to make a call that gives up and goes back to the interpreter:
 139   static CallGenerator* for_uncommon_trap(ciMethod* m,
 140                                           Deoptimization::DeoptReason reason,
 141                                           Deoptimization::DeoptAction action);
 142 
 143   // Registry for intrinsics:
 144   static CallGenerator* for_intrinsic(ciMethod* m);
 145   static void register_intrinsic(ciMethod* m, CallGenerator* cg);
 146   static CallGenerator* for_predicted_intrinsic(CallGenerator* intrinsic,
 147                                                 CallGenerator* cg);
 148   virtual Node* generate_predicate(JVMState* jvms) { return NULL; };
 149 
 150   static void print_inlining(ciMethod* callee, int inline_level, int bci, const char* msg) {
 151     if (PrintInlining)
 152       CompileTask::print_inlining(callee, inline_level, bci, msg);
 153   }
 154 };
 155 
 156 
 157 //------------------------InlineCallGenerator----------------------------------
 158 class InlineCallGenerator : public CallGenerator {
 159  protected:
 160   InlineCallGenerator(ciMethod* method) : CallGenerator(method) {}
 161 
 162  public:
 163   virtual bool      is_inline() const           { return true; }
 164 };
 165 
 166 
 167 //---------------------------WarmCallInfo--------------------------------------
 168 // A struct to collect information about a given call site.
 169 // Helps sort call sites into "hot", "medium", and "cold".
 170 // Participates in the queueing of "medium" call sites for possible inlining.
 171 class WarmCallInfo : public ResourceObj {
 172  private:
 173 
 174   CallNode*     _call;   // The CallNode which may be inlined.
 175   CallGenerator* _hot_cg;// CG for expanding the call node
 176 
 177   // These are the metrics we use to evaluate call sites:
 178 
 179   float         _count;  // How often do we expect to reach this site?
 180   float         _profit; // How much time do we expect to save by inlining?
 181   float         _work;   // How long do we expect the average call to take?
 182   float         _size;   // How big do we expect the inlined code to be?
 183 
 184   float         _heat;   // Combined score inducing total order on call sites.
 185   WarmCallInfo* _next;   // Next cooler call info in pending queue.
 186 
 187   // Count is the number of times this call site is expected to be executed.
 188   // Large count is favorable for inlining, because the extra compilation
 189   // work will be amortized more completely.
 190 
 191   // Profit is a rough measure of the amount of time we expect to save
 192   // per execution of this site if we inline it.  (1.0 == call overhead)
 193   // Large profit favors inlining.  Negative profit disables inlining.
 194 
 195   // Work is a rough measure of the amount of time a typical out-of-line
 196   // call from this site is expected to take.  (1.0 == call, no-op, return)
 197   // Small work is somewhat favorable for inlining, since methods with
 198   // short "hot" traces are more likely to inline smoothly.
 199 
 200   // Size is the number of graph nodes we expect this method to produce,
 201   // not counting the inlining of any further warm calls it may include.
 202   // Small size favors inlining, since small methods are more likely to
 203   // inline smoothly.  The size is estimated by examining the native code
 204   // if available.  The method bytecodes are also examined, assuming
 205   // empirically observed node counts for each kind of bytecode.
 206 
 207   // Heat is the combined "goodness" of a site's inlining.  If we were
 208   // omniscient, it would be the difference of two sums of future execution
 209   // times of code emitted for this site (amortized across multiple sites if
 210   // sharing applies).  The two sums are for versions of this call site with
 211   // and without inlining.
 212 
 213   // We approximate this mythical quantity by playing with averages,
 214   // rough estimates, and assumptions that history repeats itself.
 215   // The basic formula count * profit is heuristically adjusted
 216   // by looking at the expected compilation and execution times of
 217   // of the inlined call.
 218 
 219   // Note:  Some of these metrics may not be present in the final product,
 220   // but exist in development builds to experiment with inline policy tuning.
 221 
 222   // This heuristic framework does not model well the very significant
 223   // effects of multiple-level inlining.  It is possible to see no immediate
 224   // profit from inlining X->Y, but to get great profit from a subsequent
 225   // inlining X->Y->Z.
 226 
 227   // This framework does not take well into account the problem of N**2 code
 228   // size in a clique of mutually inlinable methods.
 229 
 230   WarmCallInfo*  next() const          { return _next; }
 231   void       set_next(WarmCallInfo* n) { _next = n; }
 232 
 233   static WarmCallInfo _always_hot;
 234   static WarmCallInfo _always_cold;
 235 
 236   // Constructor intitialization of always_hot and always_cold
 237   WarmCallInfo(float c, float p, float w, float s) {
 238     _call = NULL;
 239     _hot_cg = NULL;
 240     _next = NULL;
 241     _count = c;
 242     _profit = p;
 243     _work = w;
 244     _size = s;
 245     _heat = 0;
 246   }
 247 
 248  public:
 249   // Because WarmInfo objects live over the entire lifetime of the
 250   // Compile object, they are allocated into the comp_arena, which
 251   // does not get resource marked or reset during the compile process
 252   void *operator new( size_t x, Compile* C ) { return C->comp_arena()->Amalloc(x); }
 253   void operator delete( void * ) { } // fast deallocation
 254 
 255   static WarmCallInfo* always_hot();
 256   static WarmCallInfo* always_cold();
 257 
 258   WarmCallInfo() {
 259     _call = NULL;
 260     _hot_cg = NULL;
 261     _next = NULL;
 262     _count = _profit = _work = _size = _heat = 0;
 263   }
 264 
 265   CallNode* call() const { return _call; }
 266   float count()    const { return _count; }
 267   float size()     const { return _size; }
 268   float work()     const { return _work; }
 269   float profit()   const { return _profit; }
 270   float heat()     const { return _heat; }
 271 
 272   void set_count(float x)     { _count = x; }
 273   void set_size(float x)      { _size = x; }
 274   void set_work(float x)      { _work = x; }
 275   void set_profit(float x)    { _profit = x; }
 276   void set_heat(float x)      { _heat = x; }
 277 
 278   // Load initial heuristics from profiles, etc.
 279   // The heuristics can be tweaked further by the caller.
 280   void init(JVMState* call_site, ciMethod* call_method, ciCallProfile& profile, float prof_factor);
 281 
 282   static float MAX_VALUE() { return +1.0e10; }
 283   static float MIN_VALUE() { return -1.0e10; }
 284 
 285   float compute_heat() const;
 286 
 287   void set_call(CallNode* call)      { _call = call; }
 288   void set_hot_cg(CallGenerator* cg) { _hot_cg = cg; }
 289 
 290   // Do not queue very hot or very cold calls.
 291   // Make very cold ones out of line immediately.
 292   // Inline very hot ones immediately.
 293   // These queries apply various tunable limits
 294   // to the above metrics in a systematic way.
 295   // Test for coldness before testing for hotness.
 296   bool is_cold() const;
 297   bool is_hot() const;
 298 
 299   // Force a warm call to be hot.  This worklists the call node for inlining.
 300   void make_hot();
 301 
 302   // Force a warm call to be cold.  This worklists the call node for out-of-lining.
 303   void make_cold();
 304 
 305   // A reproducible total ordering, in which heat is the major key.
 306   bool warmer_than(WarmCallInfo* that);
 307 
 308   // List management.  These methods are called with the list head,
 309   // and return the new list head, inserting or removing the receiver.
 310   WarmCallInfo* insert_into(WarmCallInfo* head);
 311   WarmCallInfo* remove_from(WarmCallInfo* head);
 312 
 313 #ifndef PRODUCT
 314   void print() const;
 315   void print_all() const;
 316   int count_all() const;
 317 #endif
 318 };
 319 
 320 #endif // SHARE_VM_OPTO_CALLGENERATOR_HPP