/*

 * Copyright (c) 2015, 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.

 *

 */

#include "precompiled.hpp"

#include "classfile/javaClasses.hpp"

#include "classfile/javaClasses.inline.hpp"

#include "classfile/vmSymbols.hpp"

#include "memory/oopFactory.hpp"

#include "oops/oop.inline.hpp"

#include "oops/objArrayOop.inline.hpp"

#include "prims/stackwalk.hpp"

#include "runtime/globals.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/vframe.hpp"

#include "utilities/globalDefinitions.hpp"

// setup and cleanup actions

void StackWalkAnchor::setup_magic_on_entry(objArrayHandle classes_array) {

  classes_array->obj_at_put(magic_pos, _thread->threadObj());

  _anchor = address_value();

  assert(check_magic(classes_array), "invalid magic");

}

bool StackWalkAnchor::check_magic(objArrayHandle classes_array) {

  oop   m1 = classes_array->obj_at(magic_pos);

  jlong m2 = _anchor;

  if (m1 == _thread->threadObj() && m2 == address_value())  return true;

  return false;

}

bool StackWalkAnchor::cleanup_magic_on_exit(objArrayHandle classes_array) {

  bool ok = check_magic(classes_array);

  classes_array->obj_at_put(magic_pos, NULL);

  _anchor = 0L;

  return ok;

}

// Returns StackWalkAnchor for the current stack being traversed.

//

// Parameters:

//  thread         Current Java thread.

//  magic          Magic value used for each stack walking

//  classes_array  User-supplied buffers.  The 0th element is reserved

//                 to this StackWalkAnchor to use

//

StackWalkAnchor* StackWalkAnchor::from_current(JavaThread* thread, jlong magic,

                                               objArrayHandle classes_array)

{

  assert(thread != NULL && thread->is_Java_thread(), "");

  oop m1 = classes_array->obj_at(magic_pos);

  if (m1 != thread->threadObj())      return NULL;

  if (magic == 0L)                    return NULL;

  StackWalkAnchor* anchor = (StackWalkAnchor*) (intptr_t) magic;

  if (!anchor->is_valid_in(thread, classes_array))   return NULL;

  return anchor;

}

// Unpacks one or more frames into user-supplied buffers.

// Updates the end index, and returns the number of unpacked frames.

// Always start with the existing vfst.method and bci.

// Do not call vfst.next to advance over the last returned value.

// In other words, do not leave any stale data in the vfst.

//

// Parameters:

//   mode           Restrict which frames to be decoded.

//   vfst           vFrameStream.

//   max_nframes    Maximum number of frames to be filled.

//   start_index    Start index to the user-supplied buffers.

//   classes_array  Buffer to store classes in, starting at start_index.

//   frames_array   Buffer to store StackFrame in, starting at start_index.

//                  NULL if not used.

//   end_index      End index to the user-supplied buffers with unpacked frames.

//

// Returns the number of frames whose information was transferred into the buffers.

//

int StackWalk::fill_in_frames(jlong mode, vframeStream& vfst,

                              int max_nframes, int start_index,

                              objArrayHandle  classes_array,

                              objArrayHandle  frames_array,

                              int& end_index, TRAPS) {

  if (TraceStackWalk) {

    tty->print_cr("fill_in_frames limit=%d start=%d frames length=%d",

                  max_nframes, start_index, classes_array->length());

  }

  assert(max_nframes > 0, "invalid max_nframes");

  assert(start_index + max_nframes <= classes_array->length(), "oob");

  int frames_decoded = 0;

  for (; !vfst.at_end(); vfst.next()) {

    Method* method = vfst.method();

    int bci = vfst.bci();

    if (method == NULL) continue;

    if (!ShowHiddenFrames && StackWalk::skip_hidden_frames(mode)) {

      if (method->is_hidden()) {

        if (TraceStackWalk) {

          tty->print("  hidden method: "); method->print_short_name();

          tty->print("\n");

        }

        continue;

      }

    }

    int index = end_index++;

    if (TraceStackWalk) {

      tty->print("  %d: frame method: ", index); method->print_short_name();

      tty->print_cr(" bci=%d", bci);

    }

    classes_array->obj_at_put(index, method->method_holder()->java_mirror());

    // fill in StackFrameInfo and initialize MemberName

    if (live_frame_info(mode)) {

      Handle stackFrame(frames_array->obj_at(index));

      fill_live_stackframe(stackFrame, method, bci, vfst.java_frame(), CHECK_0);

    } else if (need_method_info(mode)) {

      Handle stackFrame(frames_array->obj_at(index));

      fill_stackframe(stackFrame, method, bci);

    }

    if (++frames_decoded >= max_nframes)  break;

  }

  return frames_decoded;

}

static oop create_primitive_value_instance(StackValueCollection* values, int i, TRAPS) {

  Klass* k = SystemDictionary::resolve_or_null(vmSymbols::java_lang_LiveStackFrameInfo(), CHECK_NULL);

  instanceKlassHandle ik (THREAD, k);

  JavaValue result(T_OBJECT);

  JavaCallArguments args;

  Symbol* signature = NULL;

  // ## TODO: type is only available in LocalVariable table, if present.

  // ## StackValue type is T_INT or T_OBJECT.

  switch (values->at(i)->type()) {

    case T_INT:

      args.push_int(values->int_at(i));

      signature = vmSymbols::asPrimitive_int_signature();

      break;

    case T_LONG:

      args.push_long(values->long_at(i));

      signature = vmSymbols::asPrimitive_long_signature();

      break;

    case T_FLOAT:

      args.push_float(values->float_at(i));

      signature = vmSymbols::asPrimitive_float_signature();

      break;

    case T_DOUBLE:

      args.push_double(values->double_at(i));

      signature = vmSymbols::asPrimitive_double_signature();

      break;

    case T_BYTE:

      args.push_int(values->int_at(i));

      signature = vmSymbols::asPrimitive_byte_signature();

      break;

    case T_SHORT:

      args.push_int(values->int_at(i));

      signature = vmSymbols::asPrimitive_short_signature();

      break;

    case T_CHAR:

      args.push_int(values->int_at(i));

      signature = vmSymbols::asPrimitive_char_signature();

      break;

    case T_BOOLEAN:

      args.push_int(values->int_at(i));

      signature = vmSymbols::asPrimitive_boolean_signature();

      break;

    case T_OBJECT:

      return values->obj_at(i)();

    case T_CONFLICT:

      // put a non-null slot

      args.push_int(0);

      signature = vmSymbols::asPrimitive_int_signature();

      break;

    default: ShouldNotReachHere();

  }

  JavaCalls::call_static(&result,

                         ik,

                         vmSymbols::asPrimitive_name(),

                         signature,

                         &args,

                         CHECK_NULL);

  return (instanceOop) result.get_jobject();

}

static objArrayHandle values_to_object_array(StackValueCollection* values, TRAPS) {

  objArrayHandle empty;

  int length = values->size();

  objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),

                                                   length, CHECK_(empty));

  objArrayHandle array_h(THREAD, array_oop);

  for (int i = 0; i < values->size(); i++) {

    StackValue* st = values->at(i);

    oop obj = create_primitive_value_instance(values, i, CHECK_(empty));

    if (obj != NULL)

      array_h->obj_at_put(i, obj);

  }

  return array_h;

}

static objArrayHandle monitors_to_object_array(GrowableArray<MonitorInfo*>* monitors, TRAPS) {

  int length = monitors->length();

  objArrayOop array_oop = oopFactory::new_objArray(SystemDictionary::Object_klass(),

                                                   length, CHECK_(objArrayHandle()));

  objArrayHandle array_h(THREAD, array_oop);

  for (int i = 0; i < length; i++) {

    MonitorInfo* monitor = monitors->at(i);

    array_h->obj_at_put(i, monitor->owner());

  }

  return array_h;

}

// Fill StackFrameInfo with declaringClass and bci and initialize memberName

void StackWalk::fill_stackframe(Handle stackFrame, const methodHandle& method, int bci) {

  java_lang_StackFrameInfo::set_declaringClass(stackFrame(), method->method_holder()->java_mirror());

  java_lang_StackFrameInfo::set_method_and_bci(stackFrame(), method, bci);

}

// Fill LiveStackFrameInfo with locals, monitors, and expressions

void StackWalk::fill_live_stackframe(Handle stackFrame, const methodHandle& method,

                                     int bci, javaVFrame* jvf, TRAPS) {

  fill_stackframe(stackFrame, method, bci);

  if (jvf != NULL) {

    StackValueCollection* locals = jvf->locals();

    StackValueCollection* expressions = jvf->expressions();

    GrowableArray<MonitorInfo*>* monitors = jvf->monitors();

    if (!locals->is_empty()) {

      objArrayHandle locals_h = values_to_object_array(locals, CHECK);

      java_lang_LiveStackFrameInfo::set_locals(stackFrame(), locals_h());

    }

    if (!expressions->is_empty()) {

      objArrayHandle expressions_h = values_to_object_array(expressions, CHECK);

      java_lang_LiveStackFrameInfo::set_operands(stackFrame(), expressions_h());

    }

    if (monitors->length() > 0) {

      objArrayHandle monitors_h = monitors_to_object_array(monitors, CHECK);

      java_lang_LiveStackFrameInfo::set_monitors(stackFrame(), monitors_h());

    }

  }

}

// Begins stack walking.

//

// Parameters:

//   stackStream    StackStream object

//   mode           Stack walking mode.

//   skip_frames    Number of frames to be skipped.

//   frame_count    Number of frames to be traversed.

//   start_index    Start index to the user-supplied buffers.

//   classes_array  Buffer to store classes in, starting at start_index.

//   frames_array   Buffer to store StackFrame in, starting at start_index.

//                  NULL if not used.

//

// Returns Object returned from AbstractStackWalker::doStackWalk call.

//

oop StackWalk::walk(Handle stackStream, jlong mode,

                    int skip_frames, int frame_count, int start_index,

                    objArrayHandle classes_array,

                    objArrayHandle frames_array,

                    TRAPS) {

  JavaThread* jt = (JavaThread*)THREAD;

  if (TraceStackWalk) {

    tty->print_cr("Start walking: mode " JLONG_FORMAT " skip %d frames batch size %d",

                  mode, skip_frames, frame_count);

  }

  if (need_method_info(mode)) {

    if (frames_array.is_null()) {

      THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", NULL);

    }

  }

  Klass* stackWalker_klass = SystemDictionary::StackWalker_klass();

  Klass* abstractStackWalker_klass = SystemDictionary::AbstractStackWalker_klass();

  methodHandle m_doStackWalk(THREAD, Universe::do_stack_walk_method());

  // Open up a traversable stream onto my stack.

  // This stream will be made available by *reference* to the inner Java call.

  StackWalkAnchor anchor(jt);

  vframeStream& vfst = anchor.vframe_stream();

  {

    // Skip all methods from AbstractStackWalker and StackWalk (enclosing method)

    if (!fill_in_stacktrace(mode)) {

      while (!vfst.at_end()) {

        InstanceKlass* ik = vfst.method()->method_holder();

        if (ik != stackWalker_klass &&

              ik != abstractStackWalker_klass && ik->super() != abstractStackWalker_klass)  {

          break;

        }

        if (TraceStackWalk) {

          tty->print("  skip "); vfst.method()->print_short_name(); tty->print("\n");

        }

        vfst.next();

      }

    }

    // For exceptions, skip Throwable::fillInStackTrace and <init> methods

    // of the exception class and superclasses

    if (fill_in_stacktrace(mode)) {

      bool skip_to_fillInStackTrace = false;

      bool skip_throwableInit_check = false;

      while (!vfst.at_end() && !skip_throwableInit_check) {

        InstanceKlass* ik = vfst.method()->method_holder();

        Method* method = vfst.method();

        if (!skip_to_fillInStackTrace) {

          if (ik == SystemDictionary::Throwable_klass() &&

              method->name() == vmSymbols::fillInStackTrace_name()) {

              // this frame will be skipped

              skip_to_fillInStackTrace = true;

          }

        } else if (!(ik->is_subclass_of(SystemDictionary::Throwable_klass()) &&

                     method->name() == vmSymbols::object_initializer_name())) {

            // there are none or we've seen them all - either way stop checking

            skip_throwableInit_check = true;

            break;

        }

        if (TraceStackWalk) {

          tty->print("stack walk: skip "); vfst.method()->print_short_name(); tty->print("\n");

        }

        vfst.next();

      }

    }

    // stack frame has been traversed individually and resume stack walk

    // from the stack frame at depth == skip_frames.

    for (int n=0; n < skip_frames && !vfst.at_end(); vfst.next(), n++) {

      if (TraceStackWalk) {

        tty->print("  skip "); vfst.method()->print_short_name();

        tty->print_cr(" frame id: " PTR_FORMAT " pc: " PTR_FORMAT,

                      p2i(vfst.frame_id()), p2i(vfst.frame_pc()));

      }

    }

  }

  // The Method* pointer in the vfst has a very short shelf life.  Grab it now.

  int end_index = start_index;

  int numFrames = 0;

  if (!vfst.at_end()) {

    numFrames = fill_in_frames(mode, vfst, frame_count, start_index, classes_array,

                               frames_array, end_index, CHECK_NULL);

    if (numFrames < 1) {

      THROW_MSG_(vmSymbols::java_lang_InternalError(), "stack walk: decode failed", NULL);

    }

  }

  // JVM_CallStackWalk walks the stack and fills in stack frames, then calls to

  // Java method java.lang.StackStreamFactory.AbstractStackWalker::doStackWalk

  // which calls the implementation to consume the stack frames.

  // When JVM_CallStackWalk returns, it invalidates the stack stream.

  JavaValue result(T_OBJECT);

  JavaCallArguments args(stackStream);

  args.push_long(anchor.address_value());

  args.push_int(skip_frames);

  args.push_int(frame_count);

  args.push_int(start_index);

  args.push_int(end_index);

  // Link the thread and vframe stream into the callee-visible object

  anchor.setup_magic_on_entry(classes_array);

  JavaCalls::call(&result, m_doStackWalk, &args, THREAD);

  // Do this before anything else happens, to disable any lingering stream objects

  bool ok = anchor.cleanup_magic_on_exit(classes_array);

  // Throw pending exception if we must

  (void) (CHECK_NULL);

  if (!ok) {

    THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers on exit", NULL);

  }

  // Return normally

  return (oop)result.get_jobject();

}

// Walk the next batch of stack frames

//

// Parameters:

//   stackStream    StackStream object

//   mode           Stack walking mode.

//   magic          Must be valid value to continue the stack walk

//   frame_count    Number of frames to be decoded.

//   start_index    Start index to the user-supplied buffers.

//   classes_array  Buffer to store classes in, starting at start_index.

//   frames_array   Buffer to store StackFrame in, starting at start_index.

//                  NULL if not used.

//

// Returns the end index of frame filled in the buffer.

//

jint StackWalk::moreFrames(Handle stackStream, jlong mode, jlong magic,

                           int frame_count, int start_index,

                           objArrayHandle classes_array,

                           objArrayHandle frames_array,

                           TRAPS)

{

  JavaThread* jt = (JavaThread*)THREAD;

  StackWalkAnchor* existing_anchor = StackWalkAnchor::from_current(jt, magic, classes_array);

  if (existing_anchor == NULL) {

    THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers", 0L);

  }

  if ((need_method_info(mode) || live_frame_info(mode)) && frames_array.is_null()) {

    THROW_MSG_(vmSymbols::java_lang_NullPointerException(), "frames_array is NULL", 0L);

  }

  if (TraceStackWalk) {

    tty->print_cr("StackWalk::moreFrames frame_count %d existing_anchor " PTR_FORMAT " start %d frames %d",

                  frame_count, p2i(existing_anchor), start_index, classes_array->length());

  }

  int end_index = start_index;

  if (frame_count <= 0) {

    return end_index;        // No operation.

  }

  int count = frame_count + start_index;

  assert (classes_array->length() >= count, "not enough space in buffers");

  StackWalkAnchor& anchor = (*existing_anchor);

  vframeStream& vfst = anchor.vframe_stream();

  if (!vfst.at_end()) {

    vfst.next();  // this was the last frame decoded in the previous batch

    if (!vfst.at_end()) {

      int n = fill_in_frames(mode, vfst, frame_count, start_index, classes_array,

                             frames_array, end_index, CHECK_0);

      if (n < 1) {

        THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: later decode failed", 0L);

      }

      return end_index;

    }

  }

  return end_index;

}