1 /*
2 * Copyright (c) 2003, 2018, 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/allocation.inline.hpp"
31 #include "memory/resourceArea.hpp"
32 #include "oops/oop.inline.hpp"
33 #include "prims/jvmtiCodeBlobEvents.hpp"
34 #include "prims/jvmtiExport.hpp"
35 #include "runtime/handles.hpp"
36 #include "runtime/handles.inline.hpp"
37 #include "runtime/vmThread.hpp"
38
39 // Support class to collect a list of the non-nmethod CodeBlobs in
40 // the CodeCache.
41 //
42 // This class actually creates a list of JvmtiCodeBlobDesc - each JvmtiCodeBlobDesc
43 // describes a single CodeBlob in the CodeCache. Note that collection is
44 // done to a static list - this is because CodeCache::blobs_do is defined
45 // as void CodeCache::blobs_do(void f(CodeBlob* nm)) and hence requires
46 // a C or static method.
47 //
48 // Usage :-
49 //
50 // CodeBlobCollector collector;
51 //
52 // collector.collect();
53 // JvmtiCodeBlobDesc* blob = collector.first();
54 // while (blob != NULL) {
55 // :
56 // blob = collector.next();
57 // }
58 //
59
60 class CodeBlobCollector : StackObj {
61 private:
62 GrowableArray<JvmtiCodeBlobDesc*>* _code_blobs; // collected blobs
63 int _pos; // iterator position
64
65 // used during a collection
66 static GrowableArray<JvmtiCodeBlobDesc*>* _global_code_blobs;
67 static void do_blob(CodeBlob* cb);
68 static void do_vtable_stub(VtableStub* vs);
69 public:
CodeBlobCollector()70 CodeBlobCollector() {
71 _code_blobs = NULL;
72 _pos = -1;
73 }
~CodeBlobCollector()74 ~CodeBlobCollector() {
75 if (_code_blobs != NULL) {
76 for (int i=0; i<_code_blobs->length(); i++) {
77 FreeHeap(_code_blobs->at(i));
78 }
79 delete _code_blobs;
80 }
81 }
82
83 // collect list of code blobs in the cache
84 void collect();
85
86 // iteration support - return first code blob
first()87 JvmtiCodeBlobDesc* first() {
88 assert(_code_blobs != NULL, "not collected");
89 if (_code_blobs->length() == 0) {
90 return NULL;
91 }
92 _pos = 0;
93 return _code_blobs->at(0);
94 }
95
96 // iteration support - return next code blob
next()97 JvmtiCodeBlobDesc* next() {
98 assert(_pos >= 0, "iteration not started");
99 if (_pos+1 >= _code_blobs->length()) {
100 return NULL;
101 }
102 return _code_blobs->at(++_pos);
103 }
104
105 };
106
107 // used during collection
108 GrowableArray<JvmtiCodeBlobDesc*>* CodeBlobCollector::_global_code_blobs;
109
110
111 // called for each CodeBlob in the CodeCache
112 //
113 // This function filters out nmethods as it is only interested in
114 // other CodeBlobs. This function also filters out CodeBlobs that have
115 // a duplicate starting address as previous blobs. This is needed to
116 // handle the case where multiple stubs are generated into a single
117 // BufferBlob.
118
do_blob(CodeBlob * cb)119 void CodeBlobCollector::do_blob(CodeBlob* cb) {
120
121 // ignore nmethods
122 if (cb->is_nmethod()) {
123 return;
124 }
125 // exclude VtableStubs, which are processed separately
126 if (cb->is_buffer_blob() && strcmp(cb->name(), "vtable chunks") == 0) {
127 return;
128 }
129
130 // check if this starting address has been seen already - the
131 // assumption is that stubs are inserted into the list before the
132 // enclosing BufferBlobs.
133 address addr = cb->code_begin();
134 for (int i=0; i<_global_code_blobs->length(); i++) {
135 JvmtiCodeBlobDesc* scb = _global_code_blobs->at(i);
136 if (addr == scb->code_begin()) {
137 return;
138 }
139 }
140
141 // record the CodeBlob details as a JvmtiCodeBlobDesc
142 JvmtiCodeBlobDesc* scb = new JvmtiCodeBlobDesc(cb->name(), cb->code_begin(), cb->code_end());
143 _global_code_blobs->append(scb);
144 }
145
146 // called for each VtableStub in VtableStubs
147
do_vtable_stub(VtableStub * vs)148 void CodeBlobCollector::do_vtable_stub(VtableStub* vs) {
149 JvmtiCodeBlobDesc* scb = new JvmtiCodeBlobDesc(vs->is_vtable_stub() ? "vtable stub" : "itable stub",
150 vs->code_begin(), vs->code_end());
151 _global_code_blobs->append(scb);
152 }
153
154 // collects a list of CodeBlobs in the CodeCache.
155 //
156 // The created list is growable array of JvmtiCodeBlobDesc - each one describes
157 // a CodeBlob. Note that the list is static - this is because CodeBlob::blobs_do
158 // requires a a C or static function so we can't use an instance function. This
159 // isn't a problem as the iteration is serial anyway as we need the CodeCache_lock
160 // to iterate over the code cache.
161 //
162 // Note that the CodeBlobs in the CodeCache will include BufferBlobs that may
163 // contain multiple stubs. As a profiler is interested in the stubs rather than
164 // the enclosing container we first iterate over the stub code descriptors so
165 // that the stubs go into the list first. do_blob will then filter out the
166 // enclosing blobs if the starting address of the enclosing blobs matches the
167 // starting address of first stub generated in the enclosing blob.
168
collect()169 void CodeBlobCollector::collect() {
170 assert_locked_or_safepoint(CodeCache_lock);
171 assert(_global_code_blobs == NULL, "checking");
172
173 // create the global list
174 _global_code_blobs = new (ResourceObj::C_HEAP, mtInternal) GrowableArray<JvmtiCodeBlobDesc*>(50,true);
175
176 // iterate over the stub code descriptors and put them in the list first.
177 for (StubCodeDesc* desc = StubCodeDesc::first(); desc != NULL; desc = StubCodeDesc::next(desc)) {
178 _global_code_blobs->append(new JvmtiCodeBlobDesc(desc->name(), desc->begin(), desc->end()));
179 }
180
181 // Vtable stubs are not described with StubCodeDesc,
182 // process them separately
183 VtableStubs::vtable_stub_do(do_vtable_stub);
184
185 // next iterate over all the non-nmethod code blobs and add them to
186 // the list - as noted above this will filter out duplicates and
187 // enclosing blobs.
188 CodeCache::blobs_do(do_blob);
189
190 // make the global list the instance list so that it can be used
191 // for other iterations.
192 _code_blobs = _global_code_blobs;
193 _global_code_blobs = NULL;
194 }
195
196
197 // Generate a DYNAMIC_CODE_GENERATED event for each non-nmethod code blob.
198
generate_dynamic_code_events(JvmtiEnv * env)199 jvmtiError JvmtiCodeBlobEvents::generate_dynamic_code_events(JvmtiEnv* env) {
200 CodeBlobCollector collector;
201
202 // First collect all the code blobs. This has to be done in a
203 // single pass over the code cache with CodeCache_lock held because
204 // there isn't any safe way to iterate over regular CodeBlobs since
205 // they can be freed at any point.
206 {
207 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
208 collector.collect();
209 }
210
211 // iterate over the collected list and post an event for each blob
212 JvmtiCodeBlobDesc* blob = collector.first();
213 while (blob != NULL) {
214 JvmtiExport::post_dynamic_code_generated(env, blob->name(), blob->code_begin(), blob->code_end());
215 blob = collector.next();
216 }
217 return JVMTI_ERROR_NONE;
218 }
219
220
221 // Generate a COMPILED_METHOD_LOAD event for each nnmethod
generate_compiled_method_load_events(JvmtiEnv * env)222 jvmtiError JvmtiCodeBlobEvents::generate_compiled_method_load_events(JvmtiEnv* env) {
223 HandleMark hm;
224
225 // Walk the CodeCache notifying for live nmethods. The code cache
226 // may be changing while this is happening which is ok since newly
227 // created nmethod will notify normally and nmethods which are freed
228 // can be safely skipped.
229 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
230 // Iterate over non-profiled and profiled nmethods
231 NMethodIterator iter(NMethodIterator::only_alive_and_not_unloading);
232 while(iter.next()) {
233 nmethod* current = iter.method();
234 // Lock the nmethod so it can't be freed
235 nmethodLocker nml(current);
236
237 // Don't hold the lock over the notify or jmethodID creation
238 MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
239 current->get_and_cache_jmethod_id();
240 JvmtiExport::post_compiled_method_load(current);
241 }
242 return JVMTI_ERROR_NONE;
243 }
244
245
246 // create a C-heap allocated address location map for an nmethod
build_jvmti_addr_location_map(nmethod * nm,jvmtiAddrLocationMap ** map_ptr,jint * map_length_ptr)247 void JvmtiCodeBlobEvents::build_jvmti_addr_location_map(nmethod *nm,
248 jvmtiAddrLocationMap** map_ptr,
249 jint *map_length_ptr)
250 {
251 ResourceMark rm;
252 jvmtiAddrLocationMap* map = NULL;
253 jint map_length = 0;
254
255
256 // Generate line numbers using PcDesc and ScopeDesc info
257 methodHandle mh(nm->method());
258
259 if (!mh->is_native()) {
260 PcDesc *pcd;
261 int pcds_in_method;
262
263 pcds_in_method = (nm->scopes_pcs_end() - nm->scopes_pcs_begin());
264 map = NEW_C_HEAP_ARRAY(jvmtiAddrLocationMap, pcds_in_method, mtInternal);
265
266 address scopes_data = nm->scopes_data_begin();
267 for( pcd = nm->scopes_pcs_begin(); pcd < nm->scopes_pcs_end(); ++pcd ) {
268 ScopeDesc sc0(nm, pcd->scope_decode_offset(), pcd->should_reexecute(), pcd->rethrow_exception(), pcd->return_oop());
269 ScopeDesc *sd = &sc0;
270 while( !sd->is_top() ) { sd = sd->sender(); }
271 int bci = sd->bci();
272 if (bci >= 0) {
273 assert(map_length < pcds_in_method, "checking");
274 map[map_length].start_address = (const void*)pcd->real_pc(nm);
275 map[map_length].location = bci;
276 ++map_length;
277 }
278 }
279 }
280
281 *map_ptr = map;
282 *map_length_ptr = map_length;
283 }
284