/*

 * Copyright (c) 1997, 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.

 *

 */

#include "precompiled.hpp"

#include "interpreter/interpreter.hpp"

#include "memory/resourceArea.hpp"

#include "memory/universe.hpp"

#include "oops/method.hpp"

#include "oops/oop.inline.hpp"

#include "prims/methodHandles.hpp"

#include "runtime/frame.inline.hpp"

#include "runtime/handles.inline.hpp"

#include "runtime/javaCalls.hpp"

#include "runtime/monitorChunk.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/signature.hpp"

#include "runtime/stubCodeGenerator.hpp"

#include "runtime/stubRoutines.hpp"

#include "vmreg_x86.inline.hpp"

#ifdef COMPILER1

#include "c1/c1_Runtime1.hpp"

#include "runtime/vframeArray.hpp"

#endif

#ifdef ASSERT

void RegisterMap::check_location_valid() {

}

#endif

// Profiling/safepoint support

bool frame::safe_for_sender(JavaThread *thread) {

  address   sp = (address)_sp;

  address   fp = (address)_fp;

  address   unextended_sp = (address)_unextended_sp;

  // consider stack guards when trying to determine "safe" stack pointers

  static size_t stack_guard_size = os::uses_stack_guard_pages() ?

    JavaThread::stack_red_zone_size() + JavaThread::stack_yellow_zone_size() : 0;

  size_t usable_stack_size = thread->stack_size() - stack_guard_size;

  // sp must be within the usable part of the stack (not in guards)

  bool sp_safe = (sp < thread->stack_base()) &&

                 (sp >= thread->stack_base() - usable_stack_size);

  if (!sp_safe) {

    return false;

  }

  // unextended sp must be within the stack and above or equal sp

  bool unextended_sp_safe = (unextended_sp < thread->stack_base()) &&

                            (unextended_sp >= sp);

  if (!unextended_sp_safe) {

    return false;

  }

  // an fp must be within the stack and above (but not equal) sp

  // second evaluation on fp+ is added to handle situation where fp is -1

  bool fp_safe = (fp < thread->stack_base() && (fp > sp) && (((fp + (return_addr_offset * sizeof(void*))) < thread->stack_base())));

  // We know sp/unextended_sp are safe only fp is questionable here

  // If the current frame is known to the code cache then we can attempt to

  // to construct the sender and do some validation of it. This goes a long way

  // toward eliminating issues when we get in frame construction code

  if (_cb != NULL ) {

    // First check if frame is complete and tester is reliable

    // Unfortunately we can only check frame complete for runtime stubs and nmethod

    // other generic buffer blobs are more problematic so we just assume they are

    // ok. adapter blobs never have a frame complete and are never ok.

    if (!_cb->is_frame_complete_at(_pc)) {

      if (_cb->is_compiled() || _cb->is_adapter_blob() || _cb->is_runtime_stub()) {

        return false;

      }

    }

    // Could just be some random pointer within the codeBlob

    if (!_cb->code_contains(_pc)) {

      return false;

    }

    // Entry frame checks

    if (is_entry_frame()) {

      // an entry frame must have a valid fp.

      return fp_safe && is_entry_frame_valid(thread);

    }

    intptr_t* sender_sp = NULL;

    intptr_t* sender_unextended_sp = NULL;

    address   sender_pc = NULL;

    intptr_t* saved_fp =  NULL;

    if (is_interpreted_frame()) {

      // fp must be safe

      if (!fp_safe) {

        return false;

      }

      sender_pc = (address) this->fp()[return_addr_offset];

      // for interpreted frames, the value below is the sender "raw" sp,

      // which can be different from the sender unextended sp (the sp seen

      // by the sender) because of current frame local variables

      sender_sp = (intptr_t*) addr_at(sender_sp_offset);

      sender_unextended_sp = (intptr_t*) this->fp()[interpreter_frame_sender_sp_offset];

      saved_fp = (intptr_t*) this->fp()[link_offset];

    } else {

      // must be some sort of compiled/runtime frame

      // fp does not have to be safe (although it could be check for c1?)

      // check for a valid frame_size, otherwise we are unlikely to get a valid sender_pc

      if (_cb->frame_size() <= 0) {

        return false;

      }

      sender_sp = _unextended_sp + _cb->frame_size();

      // Is sender_sp safe?

      if ((address)sender_sp >= thread->stack_base()) {

        return false;

      }

      sender_unextended_sp = sender_sp;

      // On Intel the return_address is always the word on the stack

      sender_pc = (address) *(sender_sp-1);

      // Note: frame::sender_sp_offset is only valid for compiled frame

      saved_fp = (intptr_t*) *(sender_sp - frame::sender_sp_offset);

    }

    // If the potential sender is the interpreter then we can do some more checking

    if (Interpreter::contains(sender_pc)) {

      // ebp is always saved in a recognizable place in any code we generate. However

      // only if the sender is interpreted/call_stub (c1 too?) are we certain that the saved ebp

      // is really a frame pointer.

      bool saved_fp_safe = ((address)saved_fp < thread->stack_base()) && (saved_fp > sender_sp);

      if (!saved_fp_safe) {

        return false;

      }

      // construct the potential sender

      frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);

      return sender.is_interpreted_frame_valid(thread);

    }

    // We must always be able to find a recognizable pc

    CodeBlob* sender_blob = CodeCache::find_blob_unsafe(sender_pc);

    if (sender_pc == NULL ||  sender_blob == NULL) {

      return false;

    }

    // Could be a zombie method

    if (sender_blob->is_zombie() || sender_blob->is_unloaded()) {

      return false;

    }

    // Could just be some random pointer within the codeBlob

    if (!sender_blob->code_contains(sender_pc)) {

      return false;

    }

    // We should never be able to see an adapter if the current frame is something from code cache

    if (sender_blob->is_adapter_blob()) {

      return false;

    }

    // Could be the call_stub

    if (StubRoutines::returns_to_call_stub(sender_pc)) {

      bool saved_fp_safe = ((address)saved_fp < thread->stack_base()) && (saved_fp > sender_sp);

      if (!saved_fp_safe) {

        return false;

      }

      // construct the potential sender

      frame sender(sender_sp, sender_unextended_sp, saved_fp, sender_pc);

      // Validate the JavaCallWrapper an entry frame must have

      address jcw = (address)sender.entry_frame_call_wrapper();

      bool jcw_safe = (jcw < thread->stack_base()) && (jcw > (address)sender.fp());

      return jcw_safe;

    }

    CompiledMethod* nm = sender_blob->as_compiled_method_or_null();

    if (nm != NULL) {

        if (nm->is_deopt_mh_entry(sender_pc) || nm->is_deopt_entry(sender_pc) ||

            nm->method()->is_method_handle_intrinsic()) {

            return false;

        }

    }

    // If the frame size is 0 something (or less) is bad because every nmethod has a non-zero frame size

    // because the return address counts against the callee's frame.

    if (sender_blob->frame_size() <= 0) {

      assert(!sender_blob->is_compiled(), "should count return address at least");

      return false;

    }

    // We should never be able to see anything here except an nmethod. If something in the

    // code cache (current frame) is called by an entity within the code cache that entity

    // should not be anything but the call stub (already covered), the interpreter (already covered)

    // or an nmethod.

    if (!sender_blob->is_compiled()) {

        return false;

    }

    // Could put some more validation for the potential non-interpreted sender

    // frame we'd create by calling sender if I could think of any. Wait for next crash in forte...

    // One idea is seeing if the sender_pc we have is one that we'd expect to call to current cb

    // We've validated the potential sender that would be created

    return true;

  }

  // Must be native-compiled frame. Since sender will try and use fp to find

  // linkages it must be safe

  if (!fp_safe) {

    return false;

  }

  // Will the pc we fetch be non-zero (which we'll find at the oldest frame)

  if ( (address) this->fp()[return_addr_offset] == NULL) return false;

  // could try and do some more potential verification of native frame if we could think of some...

  return true;

}

void frame::patch_pc(Thread* thread, address pc) {

  address* pc_addr = &(((address*) sp())[-1]);

  if (TracePcPatching) {

    tty->print_cr("patch_pc at address " INTPTR_FORMAT " [" INTPTR_FORMAT " -> " INTPTR_FORMAT "]",

                  p2i(pc_addr), p2i(*pc_addr), p2i(pc));

  }

  // Either the return address is the original one or we are going to

  // patch in the same address that's already there.

  assert(_pc == *pc_addr || pc == *pc_addr, "must be");

  *pc_addr = pc;

  _cb = CodeCache::find_blob(pc);

  address original_pc = CompiledMethod::get_deopt_original_pc(this);

  if (original_pc != NULL) {

    assert(original_pc == _pc, "expected original PC to be stored before patching");

    _deopt_state = is_deoptimized;

    // leave _pc as is

  } else {

    _deopt_state = not_deoptimized;

    _pc = pc;

  }

}

bool frame::is_interpreted_frame() const  {

  return Interpreter::contains(pc());

}

int frame::frame_size(RegisterMap* map) const {

  frame sender = this->sender(map);

  return sender.sp() - sp();

}

intptr_t* frame::entry_frame_argument_at(int offset) const {

  // convert offset to index to deal with tsi

  int index = (Interpreter::expr_offset_in_bytes(offset)/wordSize);

  // Entry frame's arguments are always in relation to unextended_sp()

  return &unextended_sp()[index];

}

// sender_sp

intptr_t* frame::interpreter_frame_sender_sp() const {

  assert(is_interpreted_frame(), "interpreted frame expected");

  return (intptr_t*) at(interpreter_frame_sender_sp_offset);

}

void frame::set_interpreter_frame_sender_sp(intptr_t* sender_sp) {

  assert(is_interpreted_frame(), "interpreted frame expected");

  ptr_at_put(interpreter_frame_sender_sp_offset, (intptr_t) sender_sp);

}

// monitor elements

BasicObjectLock* frame::interpreter_frame_monitor_begin() const {

  return (BasicObjectLock*) addr_at(interpreter_frame_monitor_block_bottom_offset);

}

BasicObjectLock* frame::interpreter_frame_monitor_end() const {

  BasicObjectLock* result = (BasicObjectLock*) *addr_at(interpreter_frame_monitor_block_top_offset);

  // make sure the pointer points inside the frame

  assert(sp() <= (intptr_t*) result, "monitor end should be above the stack pointer");

  assert((intptr_t*) result < fp(),  "monitor end should be strictly below the frame pointer");

  return result;

}

void frame::interpreter_frame_set_monitor_end(BasicObjectLock* value) {

  *((BasicObjectLock**)addr_at(interpreter_frame_monitor_block_top_offset)) = value;

}

// Used by template based interpreter deoptimization

void frame::interpreter_frame_set_last_sp(intptr_t* sp) {

    *((intptr_t**)addr_at(interpreter_frame_last_sp_offset)) = sp;

}

frame frame::sender_for_entry_frame(RegisterMap* map) const {

  assert(map != NULL, "map must be set");

  // Java frame called from C; skip all C frames and return top C

  // frame of that chunk as the sender

  JavaFrameAnchor* jfa = entry_frame_call_wrapper()->anchor();

  assert(!entry_frame_is_first(), "next Java fp must be non zero");

  assert(jfa->last_Java_sp() > sp(), "must be above this frame on stack");

  // Since we are walking the stack now this nested anchor is obviously walkable

  // even if it wasn't when it was stacked.

  if (!jfa->walkable()) {

    // Capture _last_Java_pc (if needed) and mark anchor walkable.

    jfa->capture_last_Java_pc();

  }

  map->clear();

  assert(map->include_argument_oops(), "should be set by clear");

  vmassert(jfa->last_Java_pc() != NULL, "not walkable");

  frame fr(jfa->last_Java_sp(), jfa->last_Java_fp(), jfa->last_Java_pc());

  return fr;

}

//------------------------------------------------------------------------------

// frame::verify_deopt_original_pc

//

// Verifies the calculated original PC of a deoptimization PC for the

// given unextended SP.

#ifdef ASSERT

void frame::verify_deopt_original_pc(CompiledMethod* nm, intptr_t* unextended_sp) {

  frame fr;

  // This is ugly but it's better than to change {get,set}_original_pc

  // to take an SP value as argument.  And it's only a debugging

  // method anyway.

  fr._unextended_sp = unextended_sp;

  address original_pc = nm->get_original_pc(&fr);

  assert(nm->insts_contains_inclusive(original_pc),

         "original PC must be in the main code section of the the compiled method (or must be immediately following it)");

}

#endif

//------------------------------------------------------------------------------

// frame::adjust_unextended_sp

#ifdef ASSERT

void frame::adjust_unextended_sp() {

  // On x86, sites calling method handle intrinsics and lambda forms are treated

  // as any other call site. Therefore, no special action is needed when we are

  // returning to any of these call sites.

  if (_cb != NULL) {

    CompiledMethod* sender_cm = _cb->as_compiled_method_or_null();

    if (sender_cm != NULL) {

      // If the sender PC is a deoptimization point, get the original PC.

      if (sender_cm->is_deopt_entry(_pc) ||

          sender_cm->is_deopt_mh_entry(_pc)) {

        verify_deopt_original_pc(sender_cm, _unextended_sp);

      }

    }

  }

}

#endif

//------------------------------------------------------------------------------

// frame::update_map_with_saved_link

void frame::update_map_with_saved_link(RegisterMap* map, intptr_t** link_addr) {

  // The interpreter and compiler(s) always save EBP/RBP in a known

  // location on entry. We must record where that location is

  // so this if EBP/RBP was live on callout from c2 we can find

  // the saved copy no matter what it called.

  // Since the interpreter always saves EBP/RBP if we record where it is then

  // we don't have to always save EBP/RBP on entry and exit to c2 compiled

  // code, on entry will be enough.

  map->set_location(rbp->as_VMReg(), (address) link_addr);

#ifdef AMD64

  // this is weird "H" ought to be at a higher address however the

  // oopMaps seems to have the "H" regs at the same address and the

  // vanilla register.

  // XXXX make this go away

  if (true) {

    map->set_location(rbp->as_VMReg()->next(), (address) link_addr);

  }

#endif // AMD64

}

//------------------------------------------------------------------------------

// frame::sender_for_interpreter_frame

frame frame::sender_for_interpreter_frame(RegisterMap* map) const {

  // SP is the raw SP from the sender after adapter or interpreter

  // extension.

  intptr_t* sender_sp = this->sender_sp();

  // This is the sp before any possible extension (adapter/locals).

  intptr_t* unextended_sp = interpreter_frame_sender_sp();

#if COMPILER2_OR_JVMCI

  if (map->update_map()) {

    update_map_with_saved_link(map, (intptr_t**) addr_at(link_offset));

  }

#endif // COMPILER2_OR_JVMCI

  return frame(sender_sp, unextended_sp, link(), sender_pc());

}

//------------------------------------------------------------------------------

// frame::sender_for_compiled_frame

frame frame::sender_for_compiled_frame(RegisterMap* map) const {

  assert(map != NULL, "map must be set");

  // frame owned by optimizing compiler

  assert(_cb->frame_size() >= 0, "must have non-zero frame size");

  intptr_t* sender_sp = unextended_sp() + _cb->frame_size();

  intptr_t* unextended_sp = sender_sp;

  // On Intel the return_address is always the word on the stack

  address sender_pc = (address) *(sender_sp-1);

  // This is the saved value of EBP which may or may not really be an FP.

  // It is only an FP if the sender is an interpreter frame (or C1?).

  intptr_t** saved_fp_addr = (intptr_t**) (sender_sp - frame::sender_sp_offset);

  if (map->update_map()) {

    // Tell GC to use argument oopmaps for some runtime stubs that need it.

    // For C1, the runtime stub might not have oop maps, so set this flag

    // outside of update_register_map.

    map->set_include_argument_oops(_cb->caller_must_gc_arguments(map->thread()));

    if (_cb->oop_maps() != NULL) {

      OopMapSet::update_register_map(this, map);

    }

    // Since the prolog does the save and restore of EBP there is no oopmap

    // for it so we must fill in its location as if there was an oopmap entry

    // since if our caller was compiled code there could be live jvm state in it.

    update_map_with_saved_link(map, saved_fp_addr);

  }

  assert(sender_sp != sp(), "must have changed");

  return frame(sender_sp, unextended_sp, *saved_fp_addr, sender_pc);

}

//------------------------------------------------------------------------------

// frame::sender

frame frame::sender(RegisterMap* map) const {

  // Default is we done have to follow them. The sender_for_xxx will

  // update it accordingly

  map->set_include_argument_oops(false);

  if (is_entry_frame())       return sender_for_entry_frame(map);

  if (is_interpreted_frame()) return sender_for_interpreter_frame(map);

  assert(_cb == CodeCache::find_blob(pc()),"Must be the same");