--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/opto/callGenerator.hpp	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,266 @@
+/*
+ * 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
+};