/* * Copyright 1997-2008 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. * */ // 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 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 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_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 // 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(); };