/*
 * 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() {
  _frames->obj_at_put(StackWalk::magic_pos, _thread->threadObj());
  _anchor = address_value();
  assert(check_magic(), "invalid magic");
}

bool StackWalkAnchor::check_magic() {
  oop   m1 = _frames->obj_at(StackWalk::magic_pos);
  jlong m2 = _anchor;
  if (m1 == _thread->threadObj() && m2 == address_value())  return true;
  return false;
}

bool StackWalkAnchor::cleanup_magic_on_exit() {
  bool ok = check_magic();
  _frames->obj_at_put(StackWalk::magic_pos, NULL);
  _anchor = 0L;
  return ok;
}

/**
 * Returns StackWalkAnchor for the current stack being traversed.
 *
 * @argument thread.       Current Java thread.
 * @argument magic.        Magic value used for each stack walking
 * @argument 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(StackWalk::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))   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.
 *
 * @argument mode.          Restrict which frames to be decoded.
 * @argument decode_limit.  Maximum of frames to be decoded.
 * @argument start_index.   Start index to the user-supplied buffers.
 * @argument classes_array. Buffer to store classes in, starting at start_index.
 * @argument frames_array.  Buffer to store StackFrame in, starting at start_index.
 *                          NULL if not used.
 * @argument end_index.     End index to the user-supplied buffers
 *                          with unpacked frames.
 *
 * @return Number of frames whose information was transferred into the buffers.
 */
int StackWalkAnchor::decode_frames(jlong mode, int decode_limit, int start_index,
                                   objArrayHandle  classes_array,
                                   objArrayHandle  frames_array,
                                   int& end_index, TRAPS) {
  if (TraceStackWalk) {
    tty->print_cr("decode_frames limit=%d start=%d frames length=%d",
                  decode_limit, start_index, classes_array->length());
  }
  assert(decode_limit > 0, "invalid decode_limit");
  assert(start_index + decode_limit <= 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 (StackWalk::live_frame_info(mode)) {
      Handle stackFrame(frames_array->obj_at(index));
      StackWalk::fill_live_stackframe(stackFrame, method, bci, _vfst.java_frame(), CHECK_0);
    } else if (StackWalk::need_method_info(mode)) {
      Handle stackFrame(frames_array->obj_at(index));
      StackWalk::fill_stackframe(stackFrame, method, bci);
    }
    if (++frames_decoded >= decode_limit)  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) {
  if (TraceStackWalk) {
    tty->print("     member name: "); method->print_short_name();
    tty->print_cr(" bci=%d", 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.
 *
 * @argument stackStream.   StackStream object
 * @argument mode.          Stack walking mode.
 * @argument skip_frames.   Number of frames to be skipped.
 * @argument frame_count.   Number of frames to be traversed.
 * @argument start_index.   Start index to the user-supplied buffers.
 * @argument classes_array. Buffer to store classes in, starting at start_index.
 * @argument frames_array.  Buffer to store StackFrame in, starting at start_index.
 *                          NULL if not used.
 * @return   Object returned from AbstractStackWalker::doStackWalk call.
 */
Handle StackWalk::walk(Handle stackStream, jlong mode,
                       int skip_frames, int frame_count, int start_index,
                       objArrayHandle  classes_array,
                       objArrayHandle  frames_array,
                       TRAPS)
{
  Handle empty;

  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", empty);
    }
  }

  Klass* stackWalker_klass = SystemDictionary::StackWalker_klass();
  Klass* abstractStackWalker_klass = SystemDictionary::AbstractStackWalker_klass();

  methodHandle m_doStackWalk(THREAD, Universe::stack_walker_callback_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, classes_array);
  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 = anchor.decode_frames(mode, frame_count, start_index, classes_array,
                                     frames_array, end_index, CHECK_(empty));
    if (numFrames < 1) {
      THROW_MSG_(vmSymbols::java_lang_InternalError(), "stack walk: decode failed", empty);
    }
  }

  // call StackStream::doStackWalk to do bulk traversal on the entire stack
  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();

  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();

  // Throw pending exception if we must:
  (void) (CHECK_(empty));

  if (!ok) {
    THROW_MSG_(vmSymbols::java_lang_InternalError(), "doStackWalk: corrupted buffers on exit", empty);
  }

  Handle obj(THREAD, (oop) result.get_jobject());
  // Return normally:
  return obj;

}

/*
 * Walk the next batch of stack frames
 *
 * @argument stackStream.   StackStream object
 * @argument mode.          Stack walking mode.
 * @argument magic.         Must be valid value to continue the stack walk
 * @argument frame_count.   Number of frames to be decoded.
 * @argument start_index.   Start index to the user-supplied buffers.
 * @argument classes_array. Buffer to store classes in, starting at start_index.
 * @argument frames_array.  Buffer to store StackFrame in, starting at start_index.
 *                          NULL if not used.
 * @return   End index
 */
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();  // skip java.lang.StackStream::moreStackWalk
    if (!vfst.at_end()) {
      int n = anchor.decode_frames(mode, 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;
}