/*

 * Copyright (c) 2000, 2019, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#include "code/nmethod.hpp"

#include "compiler/compileBroker.hpp"

#include "memory/allocation.hpp"

#include "runtime/vmOperations.hpp"

#include "utilities/growableArray.hpp"

// The CompilationPolicy selects which method (if any) should be compiled.

// It also decides which methods must always be compiled (i.e., are never

// interpreted).

class CompileTask;

class CompileQueue;

class CompilationPolicy : public CHeapObj<mtCompiler> {

  static CompilationPolicy* _policy;

  // m must be compiled before executing it

  static bool must_be_compiled(const methodHandle& m, int comp_level = CompLevel_all);

public:

  // If m must_be_compiled then request a compilation from the CompileBroker.

  // This supports the -Xcomp option.

  static void compile_if_required(const methodHandle& m, TRAPS);

  // m is allowed to be compiled

  static bool can_be_compiled(const methodHandle& m, int comp_level = CompLevel_all);

  // m is allowed to be osr compiled

  static bool can_be_osr_compiled(const methodHandle& m, int comp_level = CompLevel_all);

  static bool is_compilation_enabled();

  static void set_policy(CompilationPolicy* policy) { _policy = policy; }

  static CompilationPolicy* policy()                { return _policy; }

  static CompileTask* select_task_helper(CompileQueue* compile_queue);

  // Return initial compile level that is used with Xcomp

  virtual CompLevel initial_compile_level() = 0;

  virtual int compiler_count(CompLevel comp_level) = 0;

  // main notification entry, return a pointer to an nmethod if the OSR is required,

  // returns NULL otherwise.

  virtual nmethod* event(const methodHandle& method, const methodHandle& inlinee, int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread) = 0;

  // safepoint() is called at the end of the safepoint

  virtual void do_safepoint_work() = 0;

  // reprofile request

  virtual void reprofile(ScopeDesc* trap_scope, bool is_osr) = 0;

  // delay_compilation(method) can be called by any component of the runtime to notify the policy

  // that it's recommended to delay the compilation of this method.

  virtual void delay_compilation(Method* method) = 0;

  // disable_compilation() is called whenever the runtime decides to disable compilation of the

  // specified method.

  virtual void disable_compilation(Method* method) = 0;

  // Select task is called by CompileBroker. The queue is guaranteed to have at least one

  // element and is locked. The function should select one and return it.

  virtual CompileTask* select_task(CompileQueue* compile_queue) = 0;

  // Tell the runtime if we think a given method is adequately profiled.

  virtual bool is_mature(Method* method) = 0;

  // Do policy initialization

  virtual void initialize() = 0;

  virtual bool should_not_inline(ciEnv* env, ciMethod* method) { return false; }

};

// A simple compilation policy.

class SimpleCompPolicy : public CompilationPolicy {

  int _compiler_count;

 private:

  static void trace_frequency_counter_overflow(const methodHandle& m, int branch_bci, int bci);

  static void trace_osr_request(const methodHandle& method, nmethod* osr, int bci);

  static void trace_osr_completion(nmethod* osr_nm);

  void reset_counter_for_invocation_event(const methodHandle& method);

  void reset_counter_for_back_branch_event(const methodHandle& method);

  void method_invocation_event(const methodHandle& m, JavaThread* thread);

  void method_back_branch_event(const methodHandle& m, int bci, JavaThread* thread);

 public:

  SimpleCompPolicy() : _compiler_count(0) { }

  virtual CompLevel initial_compile_level() { return CompLevel_highest_tier; }

  virtual int compiler_count(CompLevel comp_level);

  virtual void do_safepoint_work();

  virtual void reprofile(ScopeDesc* trap_scope, bool is_osr);

  virtual void delay_compilation(Method* method);

  virtual void disable_compilation(Method* method);

  virtual bool is_mature(Method* method);

  virtual void initialize();

  virtual CompileTask* select_task(CompileQueue* compile_queue);

  virtual nmethod* event(const methodHandle& method, const methodHandle& inlinee, int branch_bci, int bci, CompLevel comp_level, CompiledMethod* nm, JavaThread* thread);

};