1 /* 2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #ifndef SHARE_VM_CODE_CODECACHE_HPP 26 #define SHARE_VM_CODE_CODECACHE_HPP 27 28 #include "code/codeBlob.hpp" 29 #include "memory/allocation.hpp" 30 #include "memory/heap.hpp" 31 #include "oops/instanceKlass.hpp" 32 #include "oops/oopsHierarchy.hpp" 33 34 // The CodeCache implements the code cache for various pieces of generated 35 // code, e.g., compiled java methods, runtime stubs, transition frames, etc. 36 // The entries in the CodeCache are all CodeBlob's. 37 38 // Implementation: 39 // - Each CodeBlob occupies one chunk of memory. 40 // - Like the offset table in oldspace the zone has at table for 41 // locating a method given a addess of an instruction. 42 43 class OopClosure; 44 class DepChange; 45 46 class CodeCache : AllStatic { 47 friend class VMStructs; 48 private: 49 // CodeHeap is malloc()'ed at startup and never deleted during shutdown, 50 // so that the generated assembly code is always there when it's needed. 51 // This may cause memory leak, but is necessary, for now. See 4423824, 52 // 4422213 or 4436291 for details. 53 static CodeHeap * _heap; 54 static int _number_of_blobs; 55 static int _number_of_adapters; 56 static int _number_of_nmethods; 57 static int _number_of_nmethods_with_dependencies; 58 static bool _needs_cache_clean; 59 static nmethod* _scavenge_root_nmethods; // linked via nm->scavenge_root_link() 60 static nmethod* _saved_nmethods; // Linked list of speculatively disconnected nmethods. 61 62 static void verify_if_often() PRODUCT_RETURN; 63 64 static void mark_scavenge_root_nmethods() PRODUCT_RETURN; 65 static void verify_perm_nmethods(CodeBlobClosure* f_or_null) PRODUCT_RETURN; 66 67 public: 68 69 // Initialization 70 static void initialize(); 71 72 // Allocation/administration 73 static CodeBlob* allocate(int size, bool is_critical = false); // allocates a new CodeBlob 74 static void commit(CodeBlob* cb); // called when the allocated CodeBlob has been filled 75 static int alignment_unit(); // guaranteed alignment of all CodeBlobs 76 static int alignment_offset(); // guaranteed offset of first CodeBlob byte within alignment unit (i.e., allocation header) 77 static void free(CodeBlob* cb); // frees a CodeBlob 78 static void flush(); // flushes all CodeBlobs 79 static bool contains(void *p); // returns whether p is included 80 static void blobs_do(void f(CodeBlob* cb)); // iterates over all CodeBlobs 81 static void blobs_do(CodeBlobClosure* f); // iterates over all CodeBlobs 82 static void nmethods_do(void f(nmethod* nm)); // iterates over all nmethods 83 static void alive_nmethods_do(void f(nmethod* nm)); // iterates over all alive nmethods 84 85 // Lookup 86 static CodeBlob* find_blob(void* start); 87 static nmethod* find_nmethod(void* start); 88 89 // Lookup that does not fail if you lookup a zombie method (if you call this, be sure to know 90 // what you are doing) 91 static CodeBlob* find_blob_unsafe(void* start) { 92 // NMT can walk the stack before code cache is created 93 if (_heap == NULL) return NULL; 94 95 CodeBlob* result = (CodeBlob*)_heap->find_start(start); 96 // this assert is too strong because the heap code will return the 97 // heapblock containing start. That block can often be larger than 98 // the codeBlob itself. If you look up an address that is within 99 // the heapblock but not in the codeBlob you will assert. 100 // 101 // Most things will not lookup such bad addresses. However 102 // AsyncGetCallTrace can see intermediate frames and get that kind 103 // of invalid address and so can a developer using hsfind. 104 // 105 // The more correct answer is to return NULL if blob_contains() returns 106 // false. 107 // assert(result == NULL || result->blob_contains((address)start), "found wrong CodeBlob"); 108 109 if (result != NULL && !result->blob_contains((address)start)) { 110 result = NULL; 111 } 112 return result; 113 } 114 115 // Iteration 116 static CodeBlob* first(); 117 static CodeBlob* next (CodeBlob* cb); 118 static CodeBlob* alive(CodeBlob *cb); 119 static nmethod* alive_nmethod(CodeBlob *cb); 120 static nmethod* first_nmethod(); 121 static nmethod* next_nmethod (CodeBlob* cb); 122 static int nof_blobs() { return _number_of_blobs; } 123 static int nof_adapters() { return _number_of_adapters; } 124 static int nof_nmethods() { return _number_of_nmethods; } 125 126 // GC support 127 static void gc_epilogue(); 128 static void gc_prologue(); 129 static void verify_oops(); 130 // If "unloading_occurred" is true, then unloads (i.e., breaks root links 131 // to) any unmarked codeBlobs in the cache. Sets "marked_for_unloading" 132 // to "true" iff some code got unloaded. 133 static void do_unloading(BoolObjectClosure* is_alive, bool unloading_occurred); 134 static void oops_do(OopClosure* f) { 135 CodeBlobToOopClosure oopc(f, /*do_marking=*/ false); 136 blobs_do(&oopc); 137 } 138 static void asserted_non_scavengable_nmethods_do(CodeBlobClosure* f = NULL) PRODUCT_RETURN; 139 static void scavenge_root_nmethods_do(CodeBlobClosure* f); 140 141 static nmethod* scavenge_root_nmethods() { return _scavenge_root_nmethods; } 142 static void set_scavenge_root_nmethods(nmethod* nm) { _scavenge_root_nmethods = nm; } 143 static void add_scavenge_root_nmethod(nmethod* nm); 144 static void drop_scavenge_root_nmethod(nmethod* nm); 145 static void prune_scavenge_root_nmethods(); 146 147 // Printing/debugging 148 static void print(); // prints summary 149 static void print_internals(); 150 static void verify(); // verifies the code cache 151 static void print_trace(const char* event, CodeBlob* cb, int size = 0) PRODUCT_RETURN; 152 static void print_summary(outputStream* st, bool detailed = true); // Prints a summary of the code cache usage 153 static void log_state(outputStream* st); 154 155 // The full limits of the codeCache 156 static address low_bound() { return (address) _heap->low_boundary(); } 157 static address high_bound() { return (address) _heap->high_boundary(); } 158 159 // Profiling 160 static address first_address(); // first address used for CodeBlobs 161 static address last_address(); // last address used for CodeBlobs 162 static size_t capacity() { return _heap->capacity(); } 163 static size_t max_capacity() { return _heap->max_capacity(); } 164 static size_t unallocated_capacity() { return _heap->unallocated_capacity(); } 165 static bool needs_flushing() { return unallocated_capacity() < CodeCacheFlushingMinimumFreeSpace; } 166 167 static bool needs_cache_clean() { return _needs_cache_clean; } 168 static void set_needs_cache_clean(bool v) { _needs_cache_clean = v; } 169 static void clear_inline_caches(); // clear all inline caches 170 171 static nmethod* reanimate_saved_code(Method* m); 172 static void remove_saved_code(nmethod* nm); 173 static void speculatively_disconnect(nmethod* nm); 174 175 // Deoptimization 176 static int mark_for_deoptimization(DepChange& changes); 177 #ifdef HOTSWAP 178 static int mark_for_evol_deoptimization(instanceKlassHandle dependee); 179 #endif // HOTSWAP 180 181 static void mark_all_nmethods_for_deoptimization(); 182 static int mark_for_deoptimization(Method* dependee); 183 static void make_marked_nmethods_zombies(); 184 static void make_marked_nmethods_not_entrant(); 185 186 // tells how many nmethods have dependencies 187 static int number_of_nmethods_with_dependencies(); 188 }; 189 190 #endif // SHARE_VM_CODE_CODECACHE_HPP