2
* Copyright (c) 1998, 2024, Oracle and/or its affiliates. All rights reserved.
3
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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.
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).
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.
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
25
#include "precompiled.hpp"
26
#include "code/debugInfoRec.hpp"
27
#include "code/scopeDesc.hpp"
28
#include "compiler/oopMap.hpp"
29
#include "prims/jvmtiExport.hpp"
30
#include "runtime/globals_extension.hpp"
33
// There is one DIR_Chunk for each scope and values array.
34
// A chunk can potentially be used more than once.
35
// We keep track of these chunks in order to detect
36
// repetition and enable sharing.
39
int _offset; // location in the stream of this scope
40
int _length; // number of bytes in the stream
41
int _hash; // hash of stream bytes (for quicker reuse)
42
DebugInformationRecorder* _DIR;
45
int offset() { return _offset; }
47
void* operator new(size_t ignore, DebugInformationRecorder* dir) throw() {
48
assert(ignore == sizeof(DIR_Chunk), "");
49
if (dir->_next_chunk >= dir->_next_chunk_limit) {
50
const int CHUNK = 100;
51
dir->_next_chunk = NEW_RESOURCE_ARRAY(DIR_Chunk, CHUNK);
52
dir->_next_chunk_limit = dir->_next_chunk + CHUNK;
54
return dir->_next_chunk++;
57
DIR_Chunk(int offset, int length, DebugInformationRecorder* dir) {
61
unsigned int hash = 0;
62
address p = dir->stream()->buffer() + _offset;
63
for (int i = 0; i < length; i++) {
71
DIR_Chunk* find_match(GrowableArray<DIR_Chunk*>* arr,
73
DebugInformationRecorder* dir) {
74
int end_index = arr->length();
75
int hash = this->_hash, length = this->_length;
76
address buf = dir->stream()->buffer();
77
for (int i = end_index; --i >= start_index; ) {
78
DIR_Chunk* that = arr->at(i);
79
if (hash == that->_hash &&
80
length == that->_length &&
81
0 == memcmp(buf + this->_offset, buf + that->_offset, length)) {
88
static int compare(DIR_Chunk* const & a, DIR_Chunk* const & b) {
89
if (b->_hash > a->_hash) {
92
if (b->_hash < a->_hash) {
95
if (b->_length > a->_length) {
98
if (b->_length < a->_length) {
101
address buf = a->_DIR->stream()->buffer();
102
return memcmp(buf + b->_offset, buf + a->_offset, a->_length);
106
static inline bool compute_recording_non_safepoints() {
107
if (JvmtiExport::should_post_compiled_method_load()
108
&& FLAG_IS_DEFAULT(DebugNonSafepoints)) {
109
// The default value of this flag is taken to be true,
110
// if JVMTI is looking at nmethod codes.
111
// We anticipate that JVMTI may wish to participate in profiling.
115
// If the flag is set manually, use it, whether true or false.
116
// Otherwise, if JVMTI is not in the picture, use the default setting.
117
// (This is true in debug, just for the exercise, false in product mode.)
118
return DebugNonSafepoints;
121
DebugInformationRecorder::DebugInformationRecorder(OopRecorder* oop_recorder)
122
: _recording_non_safepoints(compute_recording_non_safepoints())
125
_pcs = NEW_RESOURCE_ARRAY(PcDesc, _pcs_size);
128
_prev_safepoint_pc = PcDesc::lower_offset_limit;
130
_stream = new DebugInfoWriteStream(this, 10 * K);
131
// make sure that there is no stream_decode_offset that is zero
132
_stream->write_byte((jbyte)0xFF);
134
// make sure that we can distinguish the value "serialized_null" from offsets
135
assert(_stream->position() > serialized_null, "sanity");
137
_oop_recorder = oop_recorder;
139
_all_chunks = new GrowableArray<DIR_Chunk*>(300);
140
_next_chunk = _next_chunk_limit = nullptr;
142
add_new_pc_offset(PcDesc::lower_offset_limit); // sentinel record
144
debug_only(_recording_state = rs_null);
148
void DebugInformationRecorder::add_oopmap(int pc_offset, OopMap* map) {
149
// !!!!! Preserve old style handling of oopmaps for now
150
_oopmaps->add_gc_map(pc_offset, map);
153
void DebugInformationRecorder::add_safepoint(int pc_offset, OopMap* map) {
154
assert(!_oop_recorder->is_complete(), "not frozen yet");
155
// Store the new safepoint
158
add_oopmap(pc_offset, map);
160
add_new_pc_offset(pc_offset);
162
assert(_recording_state == rs_null, "nesting of recording calls");
163
debug_only(_recording_state = rs_safepoint);
166
void DebugInformationRecorder::add_non_safepoint(int pc_offset) {
167
assert(!_oop_recorder->is_complete(), "not frozen yet");
168
assert(_recording_non_safepoints, "must be recording non-safepoints");
170
add_new_pc_offset(pc_offset);
172
assert(_recording_state == rs_null, "nesting of recording calls");
173
debug_only(_recording_state = rs_non_safepoint);
176
void DebugInformationRecorder::add_new_pc_offset(int pc_offset) {
177
assert(_pcs_length == 0 || last_pc()->pc_offset() < pc_offset,
178
"must specify a new, larger pc offset: %d >= %d", last_pc()->pc_offset(), pc_offset);
181
if (_pcs_length == _pcs_size) {
183
int new_pcs_size = _pcs_size * 2;
184
PcDesc* new_pcs = NEW_RESOURCE_ARRAY(PcDesc, new_pcs_size);
185
for (int index = 0; index < _pcs_length; index++) {
186
new_pcs[index] = _pcs[index];
188
_pcs_size = new_pcs_size;
191
assert(_pcs_size > _pcs_length, "There must be room for after expanding");
193
_pcs[_pcs_length++] = PcDesc(pc_offset, DebugInformationRecorder::serialized_null,
194
DebugInformationRecorder::serialized_null);
198
int DebugInformationRecorder::serialize_monitor_values(GrowableArray<MonitorValue*>* monitors) {
199
if (monitors == nullptr || monitors->is_empty()) return DebugInformationRecorder::serialized_null;
200
assert(_recording_state == rs_safepoint, "must be recording a safepoint");
201
int result = stream()->position();
202
stream()->write_int(monitors->length());
203
for (int index = 0; index < monitors->length(); index++) {
204
monitors->at(index)->write_on(stream());
206
assert(result != serialized_null, "sanity");
208
// (See comment below on DebugInformationRecorder::describe_scope.)
209
int shared_result = find_sharable_decode_offset(result);
210
if (shared_result != serialized_null) {
211
stream()->set_position(result);
212
result = shared_result;
219
int DebugInformationRecorder::serialize_scope_values(GrowableArray<ScopeValue*>* values) {
220
if (values == nullptr || values->is_empty()) return DebugInformationRecorder::serialized_null;
221
assert(_recording_state == rs_safepoint, "must be recording a safepoint");
222
int result = stream()->position();
223
assert(result != serialized_null, "sanity");
224
stream()->write_int(values->length());
225
for (int index = 0; index < values->length(); index++) {
226
values->at(index)->write_on(stream());
229
// (See comment below on DebugInformationRecorder::describe_scope.)
230
int shared_result = find_sharable_decode_offset(result);
231
if (shared_result != serialized_null) {
232
stream()->set_position(result);
233
result = shared_result;
241
// These variables are put into one block to reduce relocations
242
// and make it simpler to print from the debugger.
244
struct dir_stats_struct {
250
tty->print_cr("Debug Data Chunks: %d, shared %d, non-SP's elided %d",
251
chunks_queried, chunks_shared, chunks_elided);
257
int DebugInformationRecorder::find_sharable_decode_offset(int stream_offset) {
258
NOT_PRODUCT(++dir_stats.chunks_queried);
259
int stream_length = stream()->position() - stream_offset;
260
assert(stream_offset != serialized_null, "should not be null");
261
assert(stream_length != 0, "should not be empty");
263
DIR_Chunk* ns = new(this) DIR_Chunk(stream_offset, stream_length, this);
265
DIR_Chunk* match = _all_chunks->insert_sorted<DIR_Chunk::compare>(ns);
267
// Found an existing chunk
268
NOT_PRODUCT(++dir_stats.chunks_shared);
269
assert(ns+1 == _next_chunk, "");
271
return match->offset();
273
// Inserted this chunk, so nothing to do
274
return serialized_null;
279
// must call add_safepoint before: it sets PcDesc and this routine uses
280
// the last PcDesc set
281
void DebugInformationRecorder::describe_scope(int pc_offset,
282
const methodHandle& methodH,
286
bool rethrow_exception,
287
bool is_method_handle_invoke,
289
bool has_ea_local_in_scope,
292
DebugToken* expressions,
293
DebugToken* monitors) {
294
assert(_recording_state != rs_null, "nesting of recording calls");
295
PcDesc* last_pd = last_pc();
296
assert(last_pd->pc_offset() == pc_offset, "must be last pc");
297
int sender_stream_offset = last_pd->scope_decode_offset();
298
// update the stream offset of current pc desc
299
int stream_offset = stream()->position();
300
last_pd->set_scope_decode_offset(stream_offset);
302
// Record flags into pcDesc.
303
last_pd->set_should_reexecute(reexecute);
304
last_pd->set_rethrow_exception(rethrow_exception);
305
last_pd->set_is_method_handle_invoke(is_method_handle_invoke);
306
last_pd->set_return_oop(return_oop);
307
last_pd->set_has_ea_local_in_scope(has_ea_local_in_scope);
308
last_pd->set_arg_escape(arg_escape);
310
// serialize sender stream offset
311
stream()->write_int(sender_stream_offset);
314
Metadata* method_enc;
315
if (method != nullptr) {
316
method_enc = method->constant_encoding();
317
} else if (methodH.not_null()) {
318
method_enc = methodH();
320
method_enc = nullptr;
322
int method_enc_index = oop_recorder()->find_index(method_enc);
323
stream()->write_int(method_enc_index);
324
stream()->write_bci(bci);
325
assert(method == nullptr ||
326
(method->is_native() && bci == 0) ||
327
(!method->is_native() && 0 <= bci && bci < method->code_size()) ||
328
bci == -1, "illegal bci");
330
// serialize the locals/expressions/monitors
331
stream()->write_int((intptr_t) locals);
332
stream()->write_int((intptr_t) expressions);
333
stream()->write_int((intptr_t) monitors);
335
// Here's a tricky bit. We just wrote some bytes.
336
// Wouldn't it be nice to find that we had already
337
// written those same bytes somewhere else?
338
// If we get lucky this way, reset the stream
339
// and reuse the old bytes. By the way, this
340
// trick not only shares parent scopes, but also
341
// compresses equivalent non-safepoint PcDescs.
342
int shared_stream_offset = find_sharable_decode_offset(stream_offset);
343
if (shared_stream_offset != serialized_null) {
344
stream()->set_position(stream_offset);
345
last_pd->set_scope_decode_offset(shared_stream_offset);
349
void DebugInformationRecorder::dump_object_pool(GrowableArray<ScopeValue*>* objects) {
350
guarantee( _pcs_length > 0, "safepoint must exist before describing scopes");
351
PcDesc* last_pd = &_pcs[_pcs_length-1];
352
if (objects != nullptr) {
353
for (int i = objects->length() - 1; i >= 0; i--) {
354
objects->at(i)->as_ObjectValue()->set_visited(false);
357
int offset = serialize_scope_values(objects);
358
last_pd->set_obj_decode_offset(offset);
361
void DebugInformationRecorder::end_scopes(int pc_offset, bool is_safepoint) {
362
assert(_recording_state == (is_safepoint? rs_safepoint: rs_non_safepoint),
363
"nesting of recording calls");
364
debug_only(_recording_state = rs_null);
366
// Try to compress away an equivalent non-safepoint predecessor.
367
// (This only works because we have previously recognized redundant
368
// scope trees and made them use a common scope_decode_offset.)
369
if (_pcs_length >= 2 && recording_non_safepoints()) {
370
PcDesc* last = last_pc();
371
PcDesc* prev = prev_pc();
372
// If prev is (a) not a safepoint and (b) has the same
373
// stream pointer, then it can be coalesced into the last.
374
// This is valid because non-safepoints are only sought
375
// with pc_desc_near, which (when it misses prev) will
376
// search forward until it finds last.
377
// In addition, it does not matter if the last PcDesc
378
// is for a safepoint or not.
379
if (_prev_safepoint_pc < prev->pc_offset() && prev->is_same_info(last)) {
380
assert(prev == last-1, "sane");
381
prev->set_pc_offset(pc_offset);
383
NOT_PRODUCT(++dir_stats.chunks_elided);
387
// We have just recorded this safepoint.
388
// Remember it in case the previous paragraph needs to know.
390
_prev_safepoint_pc = pc_offset;
395
bool DebugInformationRecorder::recorders_frozen() {
396
return _oop_recorder->is_complete();
399
void DebugInformationRecorder::mark_recorders_frozen() {
400
_oop_recorder->freeze();
404
DebugToken* DebugInformationRecorder::create_scope_values(GrowableArray<ScopeValue*>* values) {
405
assert(!recorders_frozen(), "not frozen yet");
406
return (DebugToken*) (intptr_t) serialize_scope_values(values);
410
DebugToken* DebugInformationRecorder::create_monitor_values(GrowableArray<MonitorValue*>* monitors) {
411
assert(!recorders_frozen(), "not frozen yet");
412
return (DebugToken*) (intptr_t) serialize_monitor_values(monitors);
416
int DebugInformationRecorder::data_size() {
417
debug_only(mark_recorders_frozen()); // mark it "frozen" for asserts
418
return _stream->position();
422
int DebugInformationRecorder::pcs_size() {
423
debug_only(mark_recorders_frozen()); // mark it "frozen" for asserts
424
if (last_pc()->pc_offset() != PcDesc::upper_offset_limit)
425
add_new_pc_offset(PcDesc::upper_offset_limit);
426
return _pcs_length * sizeof(PcDesc);
430
void DebugInformationRecorder::copy_to(nmethod* nm) {
431
nm->copy_scopes_data(stream()->buffer(), stream()->position());
432
nm->copy_scopes_pcs(_pcs, _pcs_length);
436
void DebugInformationRecorder::verify(const nmethod* code) {
441
void DebugInformationRecorder::print_statistics() {