src/hotspot/share/runtime/vframe.inline.hpp
changeset 49480 d7df2dd501ce
child 53065 2f41e4935c34
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/runtime/vframe.inline.hpp	Wed Mar 21 19:45:24 2018 -0400
@@ -0,0 +1,224 @@
+/*
+ * Copyright (c) 2018, 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.
+ *
+ */
+
+#ifndef SHARE_VM_RUNTIME_VFRAME_INLINE_HPP
+#define SHARE_VM_RUNTIME_VFRAME_INLINE_HPP
+
+#include "runtime/frame.inline.hpp"
+#include "runtime/vframe.hpp"
+
+inline vframeStreamCommon::vframeStreamCommon(JavaThread* thread) : _reg_map(thread, false) {
+  _thread = thread;
+}
+
+inline intptr_t* vframeStreamCommon::frame_id() const        { return _frame.id(); }
+
+inline bool vframeStreamCommon::is_interpreted_frame() const { return _frame.is_interpreted_frame(); }
+
+inline bool vframeStreamCommon::is_entry_frame() const       { return _frame.is_entry_frame(); }
+
+inline void vframeStreamCommon::next() {
+  // handle frames with inlining
+  if (_mode == compiled_mode    && fill_in_compiled_inlined_sender()) return;
+
+  // handle general case
+  do {
+    _frame = _frame.sender(&_reg_map);
+  } while (!fill_from_frame());
+}
+
+inline vframeStream::vframeStream(JavaThread* thread, bool stop_at_java_call_stub)
+  : vframeStreamCommon(thread) {
+  _stop_at_java_call_stub = stop_at_java_call_stub;
+
+  if (!thread->has_last_Java_frame()) {
+    _mode = at_end_mode;
+    return;
+  }
+
+  _frame = _thread->last_frame();
+  while (!fill_from_frame()) {
+    _frame = _frame.sender(&_reg_map);
+  }
+}
+
+inline bool vframeStreamCommon::fill_in_compiled_inlined_sender() {
+  if (_sender_decode_offset == DebugInformationRecorder::serialized_null) {
+    return false;
+  }
+  fill_from_compiled_frame(_sender_decode_offset);
+  return true;
+}
+
+
+inline void vframeStreamCommon::fill_from_compiled_frame(int decode_offset) {
+  _mode = compiled_mode;
+
+  // 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.
+inline void vframeStreamCommon::fill_from_compiled_native_frame() {
+  _mode = compiled_mode;
+  _sender_decode_offset = DebugInformationRecorder::serialized_null;
+  _method = nm()->method();
+  _bci = 0;
+}
+
+inline bool vframeStreamCommon::fill_from_frame() {
+  // Interpreted frame
+  if (_frame.is_interpreted_frame()) {
+    fill_from_interpreter_frame();
+    return true;
+  }
+
+  // Compiled frame
+
+  if (cb() != NULL && cb()->is_compiled()) {
+    if (nm()->is_native_method()) {
+      // Do not rely on scopeDesc since the pc might be unprecise 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->thread_state();
+
+        // 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.
+
+          return true;
+        }
+        decode_offset = DebugInformationRecorder::serialized_null;
+      } else {
+        decode_offset = pc_desc->scope_decode_offset();
+      }
+      fill_from_compiled_frame(decode_offset);
+    }
+    return true;
+  }
+
+  // End of stack?
+  if (_frame.is_first_frame() || (_stop_at_java_call_stub && _frame.is_entry_frame())) {
+    _mode = at_end_mode;
+    return true;
+  }
+
+  return false;
+}
+
+
+inline void vframeStreamCommon::fill_from_interpreter_frame() {
+  Method* method = _frame.interpreter_frame_method();
+  address   bcp    = _frame.interpreter_frame_bcp();
+  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., becasue
+  // 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;
+}
+
+#endif // SHARE_VM_RUNTIME_VFRAME_INLINE_HPP