1/*
2 * Copyright (c) 2003, 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#include "precompiled.hpp"
26#include "code/codeBlob.hpp"
27#include "code/codeCache.hpp"
28#include "code/scopeDesc.hpp"
29#include "code/vtableStubs.hpp"
30#include "memory/resourceArea.hpp"
31#include "oops/oop.inline.hpp"
32#include "prims/jvmtiCodeBlobEvents.hpp"
33#include "prims/jvmtiExport.hpp"
34#include "runtime/handles.hpp"
35#include "runtime/handles.inline.hpp"
36#include "runtime/vmThread.hpp"
37
38// Support class to collect a list of the non-nmethod CodeBlobs in
39// the CodeCache.
40//
41// This class actually creates a list of JvmtiCodeBlobDesc - each JvmtiCodeBlobDesc
42// describes a single CodeBlob in the CodeCache. Note that collection is
43// done to a static list - this is because CodeCache::blobs_do is defined
44// as void CodeCache::blobs_do(void f(CodeBlob* nm)) and hence requires
45// a C or static method.
46//
47// Usage :-
48//
49// CodeBlobCollector collector;
50//
51// collector.collect();
52// JvmtiCodeBlobDesc* blob = collector.first();
53// while (blob != NULL) {
54//   :
55//   blob = collector.next();
56// }
57//
58
59class CodeBlobCollector : StackObj {
60 private:
61  GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs;   // collected blobs
62  int _pos;                                         // iterator position
63
64  // used during a collection
65  static GrowableArray<JvmtiCodeBlobDesc*>* _global_code_blobs;
66  static void do_blob(CodeBlob* cb);
67  static void do_vtable_stub(VtableStub* vs);
68 public:
69  CodeBlobCollector() {
70    _code_blobs = NULL;
71    _pos = -1;
72  }
73  ~CodeBlobCollector() {
74    if (_code_blobs != NULL) {
75      for (int i=0; i<_code_blobs->length(); i++) {
76        FreeHeap(_code_blobs->at(i));
77      }
78      delete _code_blobs;
79    }
80  }
81
82  // collect list of code blobs in the cache
83  void collect();
84
85  // iteration support - return first code blob
86  JvmtiCodeBlobDesc* first() {
87    assert(_code_blobs != NULL, "not collected");
88    if (_code_blobs->length() == 0) {
89      return NULL;
90    }
91    _pos = 0;
92    return _code_blobs->at(0);
93  }
94
95  // iteration support - return next code blob
96  JvmtiCodeBlobDesc* next() {
97    assert(_pos >= 0, "iteration not started");
98    if (_pos+1 >= _code_blobs->length()) {
99      return NULL;
100    }
101    return _code_blobs->at(++_pos);
102  }
103
104};
105
106// used during collection
107GrowableArray<JvmtiCodeBlobDesc*>* CodeBlobCollector::_global_code_blobs;
108
109
110// called for each CodeBlob in the CodeCache
111//
112// This function filters out nmethods as it is only interested in
113// other CodeBlobs. This function also filters out CodeBlobs that have
114// a duplicate starting address as previous blobs. This is needed to
115// handle the case where multiple stubs are generated into a single
116// BufferBlob.
117
118void CodeBlobCollector::do_blob(CodeBlob* cb) {
119
120  // ignore nmethods
121  if (cb->is_nmethod()) {
122    return;
123  }
124  // exclude VtableStubs, which are processed separately
125  if (cb->is_buffer_blob() && strcmp(cb->name(), "vtable chunks") == 0) {
126    return;
127  }
128
129  // check if this starting address has been seen already - the
130  // assumption is that stubs are inserted into the list before the
131  // enclosing BufferBlobs.
132  address addr = cb->code_begin();
133  for (int i=0; i<_global_code_blobs->length(); i++) {
134    JvmtiCodeBlobDesc* scb = _global_code_blobs->at(i);
135    if (addr == scb->code_begin()) {
136      return;
137    }
138  }
139
140  // record the CodeBlob details as a JvmtiCodeBlobDesc
141  JvmtiCodeBlobDesc* scb = new JvmtiCodeBlobDesc(cb->name(), cb->code_begin(), cb->code_end());
142  _global_code_blobs->append(scb);
143}
144
145// called for each VtableStub in VtableStubs
146
147void CodeBlobCollector::do_vtable_stub(VtableStub* vs) {
148    JvmtiCodeBlobDesc* scb = new JvmtiCodeBlobDesc(vs->is_vtable_stub() ? "vtable stub" : "itable stub",
149                                                   vs->code_begin(), vs->code_end());
150    _global_code_blobs->append(scb);
151}
152
153// collects a list of CodeBlobs in the CodeCache.
154//
155// The created list is growable array of JvmtiCodeBlobDesc - each one describes
156// a CodeBlob. Note that the list is static - this is because CodeBlob::blobs_do
157// requires a a C or static function so we can't use an instance function. This
158// isn't a problem as the iteration is serial anyway as we need the CodeCache_lock
159// to iterate over the code cache.
160//
161// Note that the CodeBlobs in the CodeCache will include BufferBlobs that may
162// contain multiple stubs. As a profiler is interested in the stubs rather than
163// the enclosing container we first iterate over the stub code descriptors so
164// that the stubs go into the list first. do_blob will then filter out the
165// enclosing blobs if the starting address of the enclosing blobs matches the
166// starting address of first stub generated in the enclosing blob.
167
168void CodeBlobCollector::collect() {
169  assert_locked_or_safepoint(CodeCache_lock);
170  assert(_global_code_blobs == NULL, "checking");
171
172  // create the global list
173  _global_code_blobs = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JvmtiCodeBlobDesc*>(50,true);
174
175  // iterate over the stub code descriptors and put them in the list first.
176  for (StubCodeDesc* desc = StubCodeDesc::first(); desc != NULL; desc = StubCodeDesc::next(desc)) {
177    _global_code_blobs->append(new JvmtiCodeBlobDesc(desc->name(), desc->begin(), desc->end()));
178  }
179
180  // Vtable stubs are not described with StubCodeDesc,
181  // process them separately
182  VtableStubs::vtable_stub_do(do_vtable_stub);
183
184  // next iterate over all the non-nmethod code blobs and add them to
185  // the list - as noted above this will filter out duplicates and
186  // enclosing blobs.
187  CodeCache::blobs_do(do_blob);
188
189  // make the global list the instance list so that it can be used
190  // for other iterations.
191  _code_blobs = _global_code_blobs;
192  _global_code_blobs = NULL;
193}
194
195
196// Generate a DYNAMIC_CODE_GENERATED event for each non-nmethod code blob.
197
198jvmtiError JvmtiCodeBlobEvents::generate_dynamic_code_events(JvmtiEnv* env) {
199  CodeBlobCollector collector;
200
201  // First collect all the code blobs.  This has to be done in a
202  // single pass over the code cache with CodeCache_lock held because
203  // there isn't any safe way to iterate over regular CodeBlobs since
204  // they can be freed at any point.
205  {
206    MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
207    collector.collect();
208  }
209
210  // iterate over the collected list and post an event for each blob
211  JvmtiCodeBlobDesc* blob = collector.first();
212  while (blob != NULL) {
213    JvmtiExport::post_dynamic_code_generated(env, blob->name(), blob->code_begin(), blob->code_end());
214    blob = collector.next();
215  }
216  return JVMTI_ERROR_NONE;
217}
218
219
220// Generate a COMPILED_METHOD_LOAD event for each nnmethod
221jvmtiError JvmtiCodeBlobEvents::generate_compiled_method_load_events(JvmtiEnv* env) {
222  HandleMark hm;
223
224  // Walk the CodeCache notifying for live nmethods.  The code cache
225  // may be changing while this is happening which is ok since newly
226  // created nmethod will notify normally and nmethods which are freed
227  // can be safely skipped.
228  MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
229  // Iterate over non-profiled and profiled nmethods
230  NMethodIterator iter;
231  while(iter.next_alive()) {
232    nmethod* current = iter.method();
233    // Lock the nmethod so it can't be freed
234    nmethodLocker nml(current);
235
236    // Don't hold the lock over the notify or jmethodID creation
237    MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
238    current->get_and_cache_jmethod_id();
239    JvmtiExport::post_compiled_method_load(current);
240  }
241  return JVMTI_ERROR_NONE;
242}
243
244
245// create a C-heap allocated address location map for an nmethod
246void JvmtiCodeBlobEvents::build_jvmti_addr_location_map(nmethod *nm,
247                                                        jvmtiAddrLocationMap** map_ptr,
248                                                        jint *map_length_ptr)
249{
250  ResourceMark rm;
251  jvmtiAddrLocationMap* map = NULL;
252  jint map_length = 0;
253
254
255  // Generate line numbers using PcDesc and ScopeDesc info
256  methodHandle mh(nm->method());
257
258  if (!mh->is_native()) {
259    PcDesc *pcd;
260    int pcds_in_method;
261
262    pcds_in_method = (nm->scopes_pcs_end() - nm->scopes_pcs_begin());
263    map = NEW_C_HEAP_ARRAY(jvmtiAddrLocationMap, pcds_in_method, mtInternal);
264
265    address scopes_data = nm->scopes_data_begin();
266    for( pcd = nm->scopes_pcs_begin(); pcd < nm->scopes_pcs_end(); ++pcd ) {
267      ScopeDesc sc0(nm, pcd->scope_decode_offset(), pcd->should_reexecute(), pcd->rethrow_exception(), pcd->return_oop());
268      ScopeDesc *sd  = &sc0;
269      while( !sd->is_top() ) { sd = sd->sender(); }
270      int bci = sd->bci();
271      if (bci != InvocationEntryBci) {
272        assert(map_length < pcds_in_method, "checking");
273        map[map_length].start_address = (const void*)pcd->real_pc(nm);
274        map[map_length].location = bci;
275        ++map_length;
276      }
277    }
278  }
279
280  *map_ptr = map;
281  *map_length_ptr = map_length;
282}
283