Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * Copyright (c) 1997, 2008, 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

  * or visit www.oracle.com if you need additional information or have any

  * questions.

  *

  */

 // 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:

 //   - Each CodeBlob occupies one chunk of memory.

 //   - Like the offset table in oldspace the zone has at table for

 //     locating a method given a addess of an instruction.

 class OopClosure;

 class DepChange;

 class CodeCache : AllStatic {

   friend class VMStructs;

  private:

   // CodeHeap is malloc()'ed at startup and never deleted during shutdown,

   // so that the generated assembly code is always there when it's needed.

   // This may cause memory leak, but is necessary, for now. See 4423824,

   // 4422213 or 4436291 for details.

   static CodeHeap * _heap;

   static int _number_of_blobs;

   static int _number_of_nmethods_with_dependencies;

   static bool _needs_cache_clean;

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

   static nmethod* _saved_nmethods;          // linked via nm->saved_nmethod_look()

   static void verify_if_often() PRODUCT_RETURN;

   static void mark_scavenge_root_nmethods() PRODUCT_RETURN;

   static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN;

  public:

   // Initialization

   static void initialize();

   // Allocation/administration

   static CodeBlob* allocate(int size);              // 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 void flush();                              // flushes all CodeBlobs

   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

   // Lookup

   static CodeBlob* find_blob(void* start);

   static nmethod*  find_nmethod(void* start);

   // Lookup that does not fail if you lookup a zombie method (if you call this, be sure to know

   // what you are doing)

   static CodeBlob* find_blob_unsafe(void* start) {

     CodeBlob* result = (CodeBlob*)_heap->find_start(start);

     // this assert is too strong because the heap code will return the

     // heapblock containing start. That block can often be larger than

     // the codeBlob itself. If you look up an address that is within

     // the heapblock but not in the codeBlob you will assert.

     //

     // Most things will not lookup such bad addresses. However

     // AsyncGetCallTrace can see intermediate frames and get that kind

     // of invalid address and so can a developer using hsfind.

     //

     // The more correct answer is to return NULL if blob_contains() returns

     // false.

     // assert(result == NULL || result->blob_contains((address)start), "found wrong CodeBlob");

     if (result != NULL && !result->blob_contains((address)start)) {

       result = NULL;

     }

     return result;

   }

   // Iteration

   static CodeBlob* first();

   static CodeBlob* next (CodeBlob* cb);

   static CodeBlob* alive(CodeBlob *cb);

   static nmethod* alive_nmethod(CodeBlob *cb);

   static nmethod* first_nmethod();

   static nmethod* next_nmethod (CodeBlob* cb);

   static int       nof_blobs()                 { return _number_of_blobs; }

   // GC support

   static void gc_epilogue();

   static void gc_prologue();

   // 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,

                            OopClosure* keep_alive,

                            bool unloading_occurred);

   static void oops_do(OopClosure* f) {

     CodeBlobToOopClosure oopc(f, /*do_marking=*/ false);

     blobs_do(&oopc);

   }

   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()   PRODUCT_RETURN;          // prints summary

   static void print_internals();

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

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

   // The full limits of the codeCache

   static address  low_bound()                    { return (address) _heap->low_boundary(); }

   static address  high_bound()                   { return (address) _heap->high_boundary(); }

   // Profiling

   static address first_address();                // first address used for CodeBlobs

   static address last_address();                 // last  address used for CodeBlobs

   static size_t  capacity()                      { return _heap->capacity(); }

   static size_t  max_capacity()                  { return _heap->max_capacity(); }

   static size_t  unallocated_capacity()          { return _heap->unallocated_capacity(); }

   static bool    needs_flushing()                { return unallocated_capacity() < CodeCacheFlushingMinimumFreeSpace; }

   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

   static nmethod* find_and_remove_saved_code(methodOop m);

   static void remove_saved_code(nmethod* nm);

   static void speculatively_disconnect(nmethod* nm);

   // Deoptimization

   static int  mark_for_deoptimization(DepChange& changes);

 #ifdef HOTSWAP

   static int  mark_for_evol_deoptimization(instanceKlassHandle dependee);

 #endif // HOTSWAP

   static void mark_all_nmethods_for_deoptimization();

   static int  mark_for_deoptimization(methodOop dependee);

   static void make_marked_nmethods_zombies();

   static void make_marked_nmethods_not_entrant();

     // tells how many nmethods have dependencies

   static int number_of_nmethods_with_dependencies();

 };