/*

 * Copyright (c) 2015, 2019, 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 "logging/log.hpp"

#include "logging/logStream.hpp"

#include "memory/oopFactory.hpp"

#include "memory/universe.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/thread.inline.hpp"

#include "runtime/vframe.inline.hpp"

#include "utilities/globalDefinitions.hpp"

// setup and cleanup actions

void BaseFrameStream::setup_magic_on_entry(objArrayHandle frames_array) {

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

  _anchor = address_value();

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

}

bool BaseFrameStream::check_magic(objArrayHandle frames_array) {

  oop   m1 = frames_array->obj_at(magic_pos);

  jlong m2 = _anchor;

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

  return false;

}

bool BaseFrameStream::cleanup_magic_on_exit(objArrayHandle frames_array) {

  bool ok = check_magic(frames_array);

  frames_array->obj_at_put(magic_pos, NULL);

  _anchor = 0L;

  return ok;

}

JavaFrameStream::JavaFrameStream(JavaThread* thread, int mode)

  : BaseFrameStream(thread), _vfst(thread) {

  _need_method_info = StackWalk::need_method_info(mode);

}

void JavaFrameStream::next() { _vfst.next();}

// Returns the BaseFrameStream for the current stack being traversed.

//

// Parameters:

//  thread         Current Java thread.

//  magic          Magic value used for each stack walking

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

//                 for this BaseFrameStream to use

//

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

                                               objArrayHandle frames_array)

{

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

  oop m1 = frames_array->obj_at(magic_pos);

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

  if (magic == 0L)                    return NULL;

  BaseFrameStream* stream = (BaseFrameStream*) (intptr_t) magic;

  if (!stream->is_valid_in(thread, frames_array))   return NULL;

  return stream;

}

// 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.

//   BaseFrameStream  stream of frames

//   max_nframes      Maximum number of frames to be filled.

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

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

//                    frames array is a Class<?>[] array when only getting caller

//                    reference, and a StackFrameInfo[] array (or derivative)

//                    otherwise. It should never be null.

//   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, BaseFrameStream& stream,

                              int max_nframes, int start_index,

                              objArrayHandle  frames_array,

                              int& end_index, TRAPS) {

  log_debug(stackwalk)("fill_in_frames limit=%d start=%d frames length=%d",

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

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

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

  int frames_decoded = 0;

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

    Method* method = stream.method();

    if (method == NULL) continue;

    // skip hidden frames for default StackWalker option (i.e. SHOW_HIDDEN_FRAMES

    // not set) and when StackWalker::getCallerClass is called

    if (!ShowHiddenFrames && (skip_hidden_frames(mode) || get_caller_class(mode))) {

      if (method->is_hidden()) {

        LogTarget(Debug, stackwalk) lt;

        if (lt.is_enabled()) {

          ResourceMark rm(THREAD);

          LogStream ls(lt);

          ls.print("  hidden method: ");

          method->print_short_name(&ls);

          ls.cr();

        }

        continue;

      }

    }

    int index = end_index++;

    LogTarget(Debug, stackwalk) lt;

    if (lt.is_enabled()) {

      ResourceMark rm(THREAD);

      LogStream ls(lt);

      ls.print("  %d: frame method: ", index);

      method->print_short_name(&ls);

      ls.print_cr(" bci=%d", stream.bci());

    }

    if (!need_method_info(mode) && get_caller_class(mode) &&

          index == start_index && method->caller_sensitive()) {

      ResourceMark rm(THREAD);

      THROW_MSG_0(vmSymbols::java_lang_UnsupportedOperationException(),

        err_msg("StackWalker::getCallerClass called from @CallerSensitive '%s' method",

                method->external_name()));

    }

    // fill in StackFrameInfo and initialize MemberName

    if (++frames_decoded >= max_nframes)  break;

  }

  return frames_decoded;

}

// Fill in the LiveStackFrameInfo at the given index in frames_array

void LiveFrameStream::fill_frame(int index, objArrayHandle  frames_array,

                                 const methodHandle& method, TRAPS) {

  HandleMark hm(THREAD);

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

  fill_live_stackframe(stackFrame, method, CHECK);

}

// Fill in the StackFrameInfo at the given index in frames_array

void JavaFrameStream::fill_frame(int index, objArrayHandle  frames_array,

                                 const methodHandle& method, TRAPS) {

  if (_need_method_info) {

    HandleMark hm(THREAD);

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

    fill_stackframe(stackFrame, method, CHECK);

  } else {

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

  }

}

// Create and return a LiveStackFrame.PrimitiveSlot (if needed) for the

// StackValue at the given index. 'type' is expected to be T_INT, T_LONG,

// T_OBJECT, or T_CONFLICT.

oop LiveFrameStream::create_primitive_slot_instance(StackValueCollection* values,

                                                    int i, BasicType type, TRAPS) {

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

  InstanceKlass* ik = InstanceKlass::cast(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 (or converted to T_LONG on 64-bit)

  switch (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:

    case T_DOUBLE:

    case T_BYTE:

    case T_SHORT:

    case T_CHAR:

    case T_BOOLEAN:

      THROW_MSG_(vmSymbols::java_lang_InternalError(), "Unexpected StackValue type", NULL);

    case T_OBJECT:

      return values->obj_at(i)();

    case T_CONFLICT:

      // put a non-null slot

      #ifdef _LP64

        args.push_long(0);

        signature = vmSymbols::asPrimitive_long_signature();

      #else

        args.push_int(0);

        signature = vmSymbols::asPrimitive_int_signature();

      #endif

      break;

    default: ShouldNotReachHere();

  }

  JavaCalls::call_static(&result,

                         ik,

                         vmSymbols::asPrimitive_name(),

                         signature,

                         &args,

                         CHECK_NULL);

  return (instanceOop) result.get_jobject();

}

objArrayHandle LiveFrameStream::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);

    BasicType type = st->type();

    int index = i;

#ifdef _LP64

    if (type != T_OBJECT && type != T_CONFLICT) {

        intptr_t ret = st->get_int(); // read full 64-bit slot

        type = T_LONG;                // treat as long

        index--;                      // undo +1 in StackValueCollection::long_at

    }

#endif

    oop obj = create_primitive_slot_instance(values, index, type, CHECK_(empty));

    if (obj != NULL) {

      array_h->obj_at_put(i, obj);

    }

  }

  return array_h;

}

objArrayHandle LiveFrameStream::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 bci and initialize memberName

void BaseFrameStream::fill_stackframe(Handle stackFrame, const methodHandle& method, TRAPS) {

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

}

// Fill LiveStackFrameInfo with locals, monitors, and expressions

void LiveFrameStream::fill_live_stackframe(Handle stackFrame,

                                           const methodHandle& method, TRAPS) {

  fill_stackframe(stackFrame, method, CHECK);

  if (_jvf != NULL) {

    StackValueCollection* locals = _jvf->locals();

    StackValueCollection* expressions = _jvf->expressions();

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

    int mode = 0;

    if (_jvf->is_interpreted_frame()) {

      mode = MODE_INTERPRETED;

    } else if (_jvf->is_compiled_frame()) {

      mode = MODE_COMPILED;

    }

    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());

    }

    java_lang_LiveStackFrameInfo::set_mode(stackFrame(), mode);

  }

}

// 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.

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

//                  frames array is a Class<?>[] array when only getting caller

//                  reference, and a StackFrameInfo[] array (or derivative)

//                  otherwise. It should never be null.

//

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

//

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

                    int skip_frames, int frame_count, int start_index,

                    objArrayHandle frames_array,

                    TRAPS) {

  ResourceMark rm(THREAD);

  JavaThread* jt = (JavaThread*)THREAD;

  log_debug(stackwalk)("Start walking: mode " JLONG_FORMAT " skip %d frames batch size %d",

                       mode, skip_frames, frame_count);

  if (frames_array.is_null()) {

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

  }

  // Setup traversal onto my stack.

  if (live_frame_info(mode)) {

    assert (use_frames_array(mode), "Bad mode for get live frame");

    RegisterMap regMap(jt, true);

    LiveFrameStream stream(jt, &regMap);

    return fetchFirstBatch(stream, stackStream, mode, skip_frames, frame_count,

                           start_index, frames_array, THREAD);

  } else {

    JavaFrameStream stream(jt, mode);

    return fetchFirstBatch(stream, stackStream, mode, skip_frames, frame_count,

                           start_index, frames_array, THREAD);

  }

}

oop StackWalk::fetchFirstBatch(BaseFrameStream& stream, Handle stackStream,

                               jlong mode, int skip_frames, int frame_count,

                               int start_index, objArrayHandle frames_array, TRAPS) {

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

  {

    Klass* stackWalker_klass = SystemDictionary::StackWalker_klass();

    Klass* abstractStackWalker_klass = SystemDictionary::AbstractStackWalker_klass();

    while (!stream.at_end()) {

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

      if (ik != stackWalker_klass &&

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

        break;

      }

      LogTarget(Debug, stackwalk) lt;

      if (lt.is_enabled()) {

        ResourceMark rm(THREAD);

        LogStream ls(lt);

        ls.print("  skip ");

        stream.method()->print_short_name(&ls);

        ls.cr();

      }

      stream.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 && !stream.at_end(); stream.next(), n++) {

      LogTarget(Debug, stackwalk) lt;

      if (lt.is_enabled()) {

        ResourceMark rm(THREAD);

        LogStream ls(lt);

        ls.print("  skip ");

        stream.method()->print_short_name(&ls);

        ls.cr();

      }

    }

  }

  int end_index = start_index;

  int numFrames = 0;

  if (!stream.at_end()) {

    numFrames = fill_in_frames(mode, stream, frame_count, start_index,

                               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(stream.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

  stream.setup_magic_on_entry(frames_array);

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

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

  bool ok = stream.cleanup_magic_on_exit(frames_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.

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

//

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

//

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

                               int frame_count, int start_index,

                               objArrayHandle frames_array,

                               TRAPS)

{

  JavaThread* jt = (JavaThread*)THREAD;

  BaseFrameStream* existing_stream = BaseFrameStream::from_current(jt, magic, frames_array);

  if (existing_stream == NULL) {

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

  }

  if (frames_array.is_null()) {

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

  }

  log_debug(stackwalk)("StackWalk::fetchNextBatch frame_count %d existing_stream "

                       PTR_FORMAT " start %d frames %d",

                       frame_count, p2i(existing_stream), start_index, frames_array->length());

  int end_index = start_index;

  if (frame_count <= 0) {

    return end_index;        // No operation.

  }

  int count = frame_count + start_index;

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

  BaseFrameStream& stream = (*existing_stream);

  if (!stream.at_end()) {

    stream.next(); // advance past the last frame decoded in previous batch

    if (!stream.at_end()) {

      int n = fill_in_frames(mode, stream, frame_count, start_index,

                             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;

}