/*

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 * 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.

 *

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#ifndef SHARE_VM_CODE_CODECACHE_HPP

#define SHARE_VM_CODE_CODECACHE_HPP

#include "code/codeBlob.hpp"

#include "code/nmethod.hpp"

#include "memory/allocation.hpp"

#include "memory/heap.hpp"

#include "oops/instanceKlass.hpp"

#include "oops/oopsHierarchy.hpp"

#include "runtime/mutexLocker.hpp"

// The CodeCache implements the code cache for various pieces of generated

// code, e.g., compiled java methods, runtime stubs, transition frames, etc.

// The entries in the CodeCache are all CodeBlob's.

// -- Implementation --

// The CodeCache consists of one or more CodeHeaps, each of which contains

// CodeBlobs of a specific CodeBlobType. Currently heaps for the following

// types are available:

//  - Non-nmethods: Non-nmethods like Buffers, Adapters and Runtime Stubs

//  - Profiled nmethods: nmethods that are profiled, i.e., those

//    executed at level 2 or 3

//  - Non-Profiled nmethods: nmethods that are not profiled, i.e., those

//    executed at level 1 or 4 and native methods

//  - All: Used for code of all types if code cache segmentation is disabled.

//

// In the rare case of the non-nmethod code heap getting full, non-nmethod code

// will be stored in the non-profiled code heap as a fallback solution.

//

// Depending on the availability of compilers and TieredCompilation there

// may be fewer heaps. The size of the code heaps depends on the values of

// ReservedCodeCacheSize, NonProfiledCodeHeapSize and ProfiledCodeHeapSize

// (see CodeCache::heap_available(..) and CodeCache::initialize_heaps(..)

// for details).

//

// Code cache segmentation is controlled by the flag SegmentedCodeCache.

// If turned off, all code types are stored in a single code heap. By default

// code cache segmentation is turned on if TieredCompilation is enabled and

// ReservedCodeCacheSize >= 240 MB.

//

// All methods of the CodeCache accepting a CodeBlobType only apply to

// CodeBlobs of the given type. For example, iteration over the

// CodeBlobs of a specific type can be done by using CodeCache::first_blob(..)

// and CodeCache::next_blob(..) and providing the corresponding CodeBlobType.

//

// IMPORTANT: If you add new CodeHeaps to the code cache or change the

// existing ones, make sure to adapt the dtrace scripts (jhelper.d) for

// Solaris and BSD.

class OopClosure;

class DepChange;

class CodeCache : AllStatic {

  friend class VMStructs;

  friend class NMethodIterator;

  friend class WhiteBox;

 private:

  // CodeHeaps of the cache

  static GrowableArray<CodeHeap*>* _heaps;

  static address _low_bound;                            // Lower bound of CodeHeap addresses

  static address _high_bound;                           // Upper bound of CodeHeap addresses

  static int _number_of_blobs;                          // Total number of CodeBlobs in the cache

  static int _number_of_adapters;                       // Total number of Adapters in the cache

  static int _number_of_nmethods;                       // Total number of nmethods in the cache

  static int _number_of_nmethods_with_dependencies;     // Total number of nmethods with dependencies

  static bool _needs_cache_clean;                       // True if inline caches of the nmethods needs to be flushed

  static nmethod* _scavenge_root_nmethods;              // linked via nm->scavenge_root_link()

  static int _codemem_full_count;                       // Number of times a CodeHeap in the cache was full

  static void mark_scavenge_root_nmethods() PRODUCT_RETURN;

  static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;

  // CodeHeap management

  static void initialize_heaps();                             // Initializes the CodeHeaps

  // Creates a new heap with the given name and size, containing CodeBlobs of the given type

  static CodeHeap* get_code_heap(const CodeBlob* cb);         // Returns the CodeHeap for the given CodeBlob

  static CodeHeap* get_code_heap(int code_blob_type);         // Returns the CodeHeap for the given CodeBlobType

  // Returns the name of the VM option to set the size of the corresponding CodeHeap

  static const char* get_code_heap_flag_name(int code_blob_type);

  static bool heap_available(int code_blob_type);             // Returns true if an own CodeHeap for the given CodeBlobType is available

  static ReservedCodeSpace reserve_heap_memory(size_t size);  // Reserves one continuous chunk of memory for the CodeHeaps

  // Iteration

  static CodeBlob* first_blob(CodeHeap* heap);                // Returns the first CodeBlob on the given CodeHeap

  static CodeBlob* first_blob(int code_blob_type);            // Returns the first CodeBlob of the given type

  static CodeBlob* next_blob(CodeHeap* heap, CodeBlob* cb);   // Returns the first alive CodeBlob on the given CodeHeap

  static CodeBlob* next_blob(CodeBlob* cb);                   // Returns the next CodeBlob of the given type succeeding the given CodeBlob

  static size_t bytes_allocated_in_freelists();

  static int    allocated_segments();

  static size_t freelists_length();

 public:

  // Initialization

  static void initialize();

  // Allocation/administration

  static CodeBlob* allocate(int size, int code_blob_type); // allocates a new CodeBlob

  static void commit(CodeBlob* cb);                        // called when the allocated CodeBlob has been filled

  static int  alignment_unit();                            // guaranteed alignment of all CodeBlobs

  static int  alignment_offset();                          // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header)

  static void free(CodeBlob* cb);                          // frees a CodeBlob

  static bool contains(void *p);                           // returns whether p is included

  static void blobs_do(void f(CodeBlob* cb));              // iterates over all CodeBlobs

  static void blobs_do(CodeBlobClosure* f);                // iterates over all CodeBlobs

  static void nmethods_do(void f(nmethod* nm));            // iterates over all nmethods

  static void alive_nmethods_do(void f(nmethod* nm));      // iterates over all alive nmethods

  // Lookup

  static CodeBlob* find_blob(void* start);              // Returns the CodeBlob containing the given address

  static CodeBlob* find_blob_unsafe(void* start);       // Same as find_blob but does not fail if looking up a zombie method

  static nmethod*  find_nmethod(void* start);           // Returns the nmethod containing the given address

  static int       nof_blobs()      { return _number_of_blobs; }      // Returns the total number of CodeBlobs in the cache

  static int       nof_adapters()   { return _number_of_adapters; }   // Returns the total number of Adapters in the cache

  static int       nof_nmethods()   { return _number_of_nmethods; }   // Returns the total number of nmethods in the cache

  // GC support

  static void gc_epilogue();

  static void gc_prologue();

  static void verify_oops();

  // If "unloading_occurred" is true, then unloads (i.e., breaks root links

  // to) any unmarked codeBlobs in the cache.  Sets "marked_for_unloading"

  // to "true" iff some code got unloaded.

  static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred);

  static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN;

  static void scavenge_root_nmethods_do(CodeBlobClosure* f);

  static nmethod* scavenge_root_nmethods()            { return _scavenge_root_nmethods; }

  static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; }

  static void add_scavenge_root_nmethod(nmethod* nm);

  static void drop_scavenge_root_nmethod(nmethod* nm);

  static void prune_scavenge_root_nmethods();

  // Printing/debugging

  static void print();                           // prints summary

  static void print_internals();

  static void print_memory_overhead();

  static void verify();                          // verifies the code cache

  static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN;

  static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage

  static void log_state(outputStream* st);

  static const char* get_code_heap_name(int code_blob_type)  { return (heap_available(code_blob_type) ? get_code_heap(code_blob_type)->name() : "Unused"); }

  static void report_codemem_full(int code_blob_type, bool print);

  // Dcmd (Diagnostic commands)

  static void print_codelist(outputStream* st);

  static void print_layout(outputStream* st);

  // The full limits of the codeCache

  static address low_bound()                          { return _low_bound; }

  static address high_bound()                         { return _high_bound; }

  // Profiling

  static size_t capacity();

  static size_t unallocated_capacity(int code_blob_type);

  static size_t unallocated_capacity();

  static size_t max_capacity();

  static double reverse_free_ratio(int code_blob_type);

  static bool needs_cache_clean()                     { return _needs_cache_clean; }

  static void set_needs_cache_clean(bool v)           { _needs_cache_clean = v;    }

  static void clear_inline_caches();                  // clear all inline caches

  // Returns the CodeBlobType for nmethods of the given compilation level

  static int get_code_blob_type(int comp_level) {

    if (comp_level == CompLevel_none ||

        comp_level == CompLevel_simple ||

        comp_level == CompLevel_full_optimization) {

      // Non profiled methods

      return CodeBlobType::MethodNonProfiled;

    } else if (comp_level == CompLevel_limited_profile ||

               comp_level == CompLevel_full_profile) {

      // Profiled methods

      return CodeBlobType::MethodProfiled;

    }

    ShouldNotReachHere();

    return 0;

  }

  static void verify_clean_inline_caches();

  static void verify_icholder_relocations();

  // Deoptimization

 private:

  static int  mark_for_deoptimization(DepChange& changes);

#ifdef HOTSWAP

  static int  mark_for_evol_deoptimization(instanceKlassHandle dependee);

#endif // HOTSWAP

 public:

  static void mark_all_nmethods_for_deoptimization();

  static int  mark_for_deoptimization(Method* dependee);

  static void make_marked_nmethods_zombies();

  static void make_marked_nmethods_not_entrant();

  // Flushing and deoptimization

  static void flush_dependents_on(instanceKlassHandle dependee);

  static void flush_dependents_on(Handle call_site, Handle method_handle);

#ifdef HOTSWAP

  // Flushing and deoptimization in case of evolution

  static void flush_evol_dependents_on(instanceKlassHandle dependee);

#endif // HOTSWAP

  // Support for fullspeed debugging

  static void flush_dependents_on_method(methodHandle dependee);

  // tells how many nmethods have dependencies

  static int number_of_nmethods_with_dependencies();

  static int get_codemem_full_count() { return _codemem_full_count; }

};

// Iterator to iterate over nmethods in the CodeCache.

class NMethodIterator : public StackObj {

 private:

  CodeBlob* _code_blob;   // Current CodeBlob

  int _code_blob_type;    // Refers to current CodeHeap

 public:

  NMethodIterator() {

    initialize(NULL); // Set to NULL, initialized by first call to next()

  }

  NMethodIterator(nmethod* nm) {

    initialize(nm);

  }

  // Advance iterator to next nmethod

  bool next() {

    assert_locked_or_safepoint(CodeCache_lock);

    assert(_code_blob_type < CodeBlobType::NumTypes, "end reached");

    bool result = next_nmethod();

    while (!result && (_code_blob_type < CodeBlobType::MethodProfiled)) {

      // Advance to next code heap if segmented code cache

      _code_blob_type++;

      result = next_nmethod();

    }

    return result;

  }

  // Advance iterator to next alive nmethod

  bool next_alive() {

    bool result = next();

    while(result && !_code_blob->is_alive()) {

      result = next();

    }

    return result;

  }

  bool end()        const   { return _code_blob == NULL; }

  nmethod* method() const   { return (nmethod*)_code_blob; }

private:

  // Initialize iterator to given nmethod

  void initialize(nmethod* nm) {

    _code_blob = (CodeBlob*)nm;

    if (!SegmentedCodeCache) {

      // Iterate over all CodeBlobs

      _code_blob_type = CodeBlobType::All;

    } else if (nm != NULL) {

      _code_blob_type = CodeCache::get_code_blob_type(nm->comp_level());

    } else {

      // Only iterate over method code heaps, starting with non-profiled

      _code_blob_type = CodeBlobType::MethodNonProfiled;

    }

  }

  // Advance iterator to the next nmethod in the current code heap

  bool next_nmethod() {

    // Get first method CodeBlob

    if (_code_blob == NULL) {

      _code_blob = CodeCache::first_blob(_code_blob_type);

      if (_code_blob == NULL) {

        return false;

      } else if (_code_blob->is_nmethod()) {

        return true;

      }

    }

    // Search for next method CodeBlob

    _code_blob = CodeCache::next_blob(_code_blob);

    while (_code_blob != NULL && !_code_blob->is_nmethod()) {

      _code_blob = CodeCache::next_blob(_code_blob);

    }

    return _code_blob != NULL;

  }

};

#endif // SHARE_VM_CODE_CODECACHE_HPP