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 static double reverse_free_ratio();
167
168 static bool needs_cache_clean() { return _needs_cache_clean; }
169 static void set_needs_cache_clean(bool v) { _needs_cache_clean = v; }
170 static void clear_inline_caches(); // clear all inline caches
171
172 static nmethod* reanimate_saved_code(Method* m);
173 static void remove_saved_code(nmethod* nm);
174 static void speculatively_disconnect(nmethod* nm);
175
176 // Deoptimization
177 static int mark_for_deoptimization(DepChange& changes);
178 #ifdef HOTSWAP
179 static int mark_for_evol_deoptimization(instanceKlassHandle dependee);
180 #endif // HOTSWAP
181
182 static void mark_all_nmethods_for_deoptimization();
183 static int mark_for_deoptimization(Method* dependee);
184 static void make_marked_nmethods_zombies();
185 static void make_marked_nmethods_not_entrant();
186
187 // tells how many nmethods have dependencies
188 static int number_of_nmethods_with_dependencies();
189 };
190
191 #endif // SHARE_VM_CODE_CODECACHE_HPP