/* * Copyright (c) 2018, 2022, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. *
*/
inlinevoid vframeStreamCommon::next() { // handle frames with inlining if (_mode == compiled_mode && fill_in_compiled_inlined_sender()) return;
// handle general case do { bool is_enterSpecial_frame = false; if (Continuation::is_continuation_enterSpecial(_frame)) {
assert(!_reg_map.in_cont(), "");
assert(_cont_entry != NULL, ""); // Reading oops are only safe if process_frames() is true, and we fix the oops.
assert(!_reg_map.process_frames() || _cont_entry->cont_oop(_reg_map.thread()) != NULL, "_cont: " INTPTR_FORMAT, p2i(_cont_entry));
is_enterSpecial_frame = true;
// Range check to detect ridiculous offsets. if (decode_offset == DebugInformationRecorder::serialized_null ||
decode_offset < 0 ||
decode_offset >= nm()->scopes_data_size()) { // 6379830 AsyncGetCallTrace sometimes feeds us wild frames. // If we read nmethod::scopes_data at serialized_null (== 0) // or if read some at other invalid offset, invalid values will be decoded. // Based on these values, invalid heap locations could be referenced // that could lead to crashes in product mode. // Therefore, do not use the decode offset if invalid, but fill the frame // as it were a native compiled frame (no Java-level assumptions). #ifdef ASSERT if (WizardMode) {
ttyLocker ttyl;
tty->print_cr("Error in fill_from_frame: pc_desc for "
INTPTR_FORMAT " not found or invalid at %d",
p2i(_frame.pc()), decode_offset);
nm()->print();
nm()->method()->print_codes();
nm()->print_code();
nm()->print_pcs();
}
found_bad_method_frame(); #endif // Provide a cheap fallback in product mode. (See comment above.)
fill_from_compiled_native_frame(); return;
}
// Decode first part of scopeDesc
DebugInfoReadStream buffer(nm(), decode_offset);
_sender_decode_offset = buffer.read_int();
_method = buffer.read_method();
_bci = buffer.read_bci();
assert(_method->is_method(), "checking type of decoded method");
}
// The native frames are handled specially. We do not rely on ScopeDesc info // since the pc might not be exact due to the _last_native_pc trick. inlinevoid vframeStreamCommon::fill_from_compiled_native_frame() {
_mode = compiled_mode;
_sender_decode_offset = DebugInformationRecorder::serialized_null;
_decode_offset = DebugInformationRecorder::serialized_null;
_vframe_id = 0;
_method = nm()->method();
_bci = 0;
}
if (cb() != NULL && cb()->is_compiled()) {
assert(nm()->method() != NULL, "must be"); if (nm()->is_native_method()) { // Do not rely on scopeDesc since the pc might be imprecise due to the _last_native_pc trick.
fill_from_compiled_native_frame();
} else {
PcDesc* pc_desc = nm()->pc_desc_at(_frame.pc()); int decode_offset; if (pc_desc == NULL) { // Should not happen, but let fill_from_compiled_frame handle it.
// If we are trying to walk the stack of a thread that is not // at a safepoint (like AsyncGetCallTrace would do) then this is an // acceptable result. [ This is assuming that safe_for_sender // is so bullet proof that we can trust the frames it produced. ] // // So if we see that the thread is not safepoint safe // then simply produce the method and a bci of zero // and skip the possibility of decoding any inlining that // may be present. That is far better than simply stopping (or // asserting. If however the thread is safepoint safe this // is the sign of a compiler bug and we'll let // fill_from_compiled_frame handle it.
JavaThreadState state = _thread != NULL ? _thread->thread_state() : _thread_in_Java;
// in_Java should be good enough to test safepoint safety // if state were say in_Java_trans then we'd expect that // the pc would have already been slightly adjusted to // one that would produce a pcDesc since the trans state // would be one that might in fact anticipate a safepoint
if (state == _thread_in_Java ) { // This will get a method a zero bci and no inlining. // Might be nice to have a unique bci to signify this // particular case but for now zero will do.
fill_from_compiled_native_frame();
// There is something to be said for setting the mode to // at_end_mode to prevent trying to walk further up the // stack. There is evidence that if we walk any further // that we could produce a bad stack chain. However until // we see evidence that allowing this causes us to find // frames bad enough to cause segv's or assertion failures // we don't do it as while we may get a bad call chain the // probability is much higher (several magnitudes) that we // get good data.
inlinevoid vframeStreamCommon::fill_from_interpreter_frame() {
Method* method;
address bcp; if (!_reg_map.in_cont()) {
method = _frame.interpreter_frame_method();
bcp = _frame.interpreter_frame_bcp();
} else {
method = _reg_map.stack_chunk()->interpreter_frame_method(_frame);
bcp = _reg_map.stack_chunk()->interpreter_frame_bcp(_frame);
} int bci = method->validate_bci_from_bcp(bcp); // 6379830 AsyncGetCallTrace sometimes feeds us wild frames. // AsyncGetCallTrace interrupts the VM asynchronously. As a result // it is possible to access an interpreter frame for which // no Java-level information is yet available (e.g., because // the frame was being created when the VM interrupted it). // In this scenario, pretend that the interpreter is at the point // of entering the method. if (bci < 0) {
DEBUG_ONLY(found_bad_method_frame();)
bci = 0;
}
_mode = interpreted_mode;
_method = method;
_bci = bci;
}
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