/*

 * Copyright (c) 1997, 2012, 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 "code/codeCache.hpp"

#include "code/compiledIC.hpp"

#include "code/nmethod.hpp"

#include "code/relocInfo.hpp"

#include "memory/resourceArea.hpp"

#include "runtime/stubCodeGenerator.hpp"

#include "utilities/copy.hpp"

const RelocationHolder RelocationHolder::none; // its type is relocInfo::none

// Implementation of relocInfo

#ifdef ASSERT

relocInfo::relocInfo(relocType t, int off, int f) {

  assert(t != data_prefix_tag, "cannot build a prefix this way");

  assert((t & type_mask) == t, "wrong type");

  assert((f & format_mask) == f, "wrong format");

  assert(off >= 0 && off < offset_limit(), "offset out off bounds");

  assert((off & (offset_unit-1)) == 0, "misaligned offset");

  (*this) = relocInfo(t, RAW_BITS, off, f);

}

#endif

void relocInfo::initialize(CodeSection* dest, Relocation* reloc) {

  relocInfo* data = this+1;  // here's where the data might go

  dest->set_locs_end(data);  // sync end: the next call may read dest.locs_end

  reloc->pack_data_to(dest); // maybe write data into locs, advancing locs_end

  relocInfo* data_limit = dest->locs_end();

  if (data_limit > data) {

    relocInfo suffix = (*this);

    data_limit = this->finish_prefix((short*) data_limit);

    // Finish up with the suffix.  (Hack note: pack_data_to might edit this.)

    *data_limit = suffix;

    dest->set_locs_end(data_limit+1);

  }

}

relocInfo* relocInfo::finish_prefix(short* prefix_limit) {

  assert(sizeof(relocInfo) == sizeof(short), "change this code");

  short* p = (short*)(this+1);

  assert(prefix_limit >= p, "must be a valid span of data");

  int plen = prefix_limit - p;

  if (plen == 0) {

    debug_only(_value = 0xFFFF);

    return this;                         // no data: remove self completely

  }

  if (plen == 1 && fits_into_immediate(p[0])) {

    (*this) = immediate_relocInfo(p[0]); // move data inside self

    return this+1;

  }

  // cannot compact, so just update the count and return the limit pointer

  (*this) = prefix_relocInfo(plen);   // write new datalen

  assert(data() + datalen() == prefix_limit, "pointers must line up");

  return (relocInfo*)prefix_limit;

}

void relocInfo::set_type(relocType t) {

  int old_offset = addr_offset();

  int old_format = format();

  (*this) = relocInfo(t, old_offset, old_format);

  assert(type()==(int)t, "sanity check");

  assert(addr_offset()==old_offset, "sanity check");

  assert(format()==old_format, "sanity check");

}

void relocInfo::set_format(int f) {

  int old_offset = addr_offset();

  assert((f & format_mask) == f, "wrong format");

  _value = (_value & ~(format_mask << offset_width)) | (f << offset_width);

  assert(addr_offset()==old_offset, "sanity check");

}

void relocInfo::change_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type, relocType new_type) {

  bool found = false;

  while (itr->next() && !found) {

    if (itr->addr() == pc) {

      assert(itr->type()==old_type, "wrong relocInfo type found");

      itr->current()->set_type(new_type);

      found=true;

    }

  }

  assert(found, "no relocInfo found for pc");

}

void relocInfo::remove_reloc_info_for_address(RelocIterator *itr, address pc, relocType old_type) {

  change_reloc_info_for_address(itr, pc, old_type, none);

}

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

// Implementation of RelocIterator

void RelocIterator::initialize(nmethod* nm, address begin, address limit) {

  initialize_misc();

  if (nm == NULL && begin != NULL) {

    // allow nmethod to be deduced from beginning address

    CodeBlob* cb = CodeCache::find_blob(begin);

    nm = cb->as_nmethod_or_null();

  }

  assert(nm != NULL, "must be able to deduce nmethod from other arguments");

  _code    = nm;

  _current = nm->relocation_begin() - 1;

  _end     = nm->relocation_end();

  _addr    = nm->content_begin();

  // Initialize code sections.

  _section_start[CodeBuffer::SECT_CONSTS] = nm->consts_begin();

  _section_start[CodeBuffer::SECT_INSTS ] = nm->insts_begin() ;

  _section_start[CodeBuffer::SECT_STUBS ] = nm->stub_begin()  ;

  _section_end  [CodeBuffer::SECT_CONSTS] = nm->consts_end()  ;

  _section_end  [CodeBuffer::SECT_INSTS ] = nm->insts_end()   ;

  _section_end  [CodeBuffer::SECT_STUBS ] = nm->stub_end()    ;

  assert(!has_current(), "just checking");

  assert(begin == NULL || begin >= nm->code_begin(), "in bounds");

  assert(limit == NULL || limit <= nm->code_end(),   "in bounds");

  set_limits(begin, limit);

}

RelocIterator::RelocIterator(CodeSection* cs, address begin, address limit) {

  initialize_misc();

  _current = cs->locs_start()-1;

  _end     = cs->locs_end();

  _addr    = cs->start();

  _code    = NULL; // Not cb->blob();

  CodeBuffer* cb = cs->outer();

  assert((int) SECT_LIMIT == CodeBuffer::SECT_LIMIT, "my copy must be equal");

  for (int n = (int) CodeBuffer::SECT_FIRST; n < (int) CodeBuffer::SECT_LIMIT; n++) {

    CodeSection* cs = cb->code_section(n);

    _section_start[n] = cs->start();

    _section_end  [n] = cs->end();

  }

  assert(!has_current(), "just checking");

  assert(begin == NULL || begin >= cs->start(), "in bounds");

  assert(limit == NULL || limit <= cs->end(),   "in bounds");

  set_limits(begin, limit);

}

enum { indexCardSize = 128 };

struct RelocIndexEntry {

  jint addr_offset;          // offset from header_end of an addr()

  jint reloc_offset;         // offset from header_end of a relocInfo (prefix)

};

bool RelocIterator::addr_in_const() const {

  const int n = CodeBuffer::SECT_CONSTS;

  return section_start(n) <= addr() && addr() < section_end(n);

}

static inline int num_cards(int code_size) {

  return (code_size-1) / indexCardSize;

}

int RelocIterator::locs_and_index_size(int code_size, int locs_size) {

  if (!UseRelocIndex)  return locs_size;   // no index

  code_size = round_to(code_size, oopSize);

  locs_size = round_to(locs_size, oopSize);

  int index_size = num_cards(code_size) * sizeof(RelocIndexEntry);

  // format of indexed relocs:

  //   relocation_begin:   relocInfo ...

  //   index:              (addr,reloc#) ...

  //                       indexSize           :relocation_end

  return locs_size + index_size + BytesPerInt;

}

void RelocIterator::create_index(relocInfo* dest_begin, int dest_count, relocInfo* dest_end) {

  address relocation_begin = (address)dest_begin;

  address relocation_end   = (address)dest_end;

  int     total_size       = relocation_end - relocation_begin;

  int     locs_size        = dest_count * sizeof(relocInfo);

  if (!UseRelocIndex) {

    Copy::fill_to_bytes(relocation_begin + locs_size, total_size-locs_size, 0);

    return;

  }

  int     index_size       = total_size - locs_size - BytesPerInt;      // find out how much space is left

  int     ncards           = index_size / sizeof(RelocIndexEntry);

  assert(total_size == locs_size + index_size + BytesPerInt, "checkin'");

  assert(index_size >= 0 && index_size % sizeof(RelocIndexEntry) == 0, "checkin'");

  jint*   index_size_addr  = (jint*)relocation_end - 1;

  assert(sizeof(jint) == BytesPerInt, "change this code");

  *index_size_addr = index_size;

  if (index_size != 0) {

    assert(index_size > 0, "checkin'");

    RelocIndexEntry* index = (RelocIndexEntry *)(relocation_begin + locs_size);

    assert(index == (RelocIndexEntry*)index_size_addr - ncards, "checkin'");

    // walk over the relocations, and fill in index entries as we go

    RelocIterator iter;

    const address    initial_addr    = NULL;

    relocInfo* const initial_current = dest_begin - 1;  // biased by -1 like elsewhere

    iter._code    = NULL;

    iter._addr    = initial_addr;

    iter._limit   = (address)(intptr_t)(ncards * indexCardSize);

    iter._current = initial_current;

    iter._end     = dest_begin + dest_count;

    int i = 0;

    address next_card_addr = (address)indexCardSize;

    int addr_offset = 0;

    int reloc_offset = 0;

    while (true) {

      // Checkpoint the iterator before advancing it.

      addr_offset  = iter._addr    - initial_addr;

      reloc_offset = iter._current - initial_current;

      if (!iter.next())  break;

      while (iter.addr() >= next_card_addr) {

        index[i].addr_offset  = addr_offset;

        index[i].reloc_offset = reloc_offset;

        i++;

        next_card_addr += indexCardSize;

      }

    }

    while (i < ncards) {

      index[i].addr_offset  = addr_offset;

      index[i].reloc_offset = reloc_offset;

      i++;

    }

  }

}

void RelocIterator::set_limits(address begin, address limit) {

  int index_size = 0;

  if (UseRelocIndex && _code != NULL) {

    index_size = ((jint*)_end)[-1];

    _end = (relocInfo*)( (address)_end - index_size - BytesPerInt );

  }

  _limit = limit;

  // the limit affects this next stuff:

  if (begin != NULL) {

#ifdef ASSERT

    // In ASSERT mode we do not actually use the index, but simply

    // check that its contents would have led us to the right answer.

    address addrCheck = _addr;

    relocInfo* infoCheck = _current;

#endif // ASSERT

    if (index_size > 0) {

      // skip ahead

      RelocIndexEntry* index       = (RelocIndexEntry*)_end;

      RelocIndexEntry* index_limit = (RelocIndexEntry*)((address)index + index_size);

      assert(_addr == _code->code_begin(), "_addr must be unadjusted");

      int card = (begin - _addr) / indexCardSize;

      if (card > 0) {

        if (index+card-1 < index_limit)  index += card-1;

        else                             index = index_limit - 1;

#ifdef ASSERT

        addrCheck = _addr    + index->addr_offset;

        infoCheck = _current + index->reloc_offset;

#else

        // Advance the iterator immediately to the last valid state

        // for the previous card.  Calling "next" will then advance

        // it to the first item on the required card.

        _addr    += index->addr_offset;

        _current += index->reloc_offset;

#endif // ASSERT

      }

    }

    relocInfo* backup;

    address    backup_addr;

    while (true) {

      backup      = _current;

      backup_addr = _addr;

#ifdef ASSERT

      if (backup == infoCheck) {

        assert(backup_addr == addrCheck, "must match"); addrCheck = NULL; infoCheck = NULL;

      } else {

        assert(addrCheck == NULL || backup_addr <= addrCheck, "must not pass addrCheck");

      }

#endif // ASSERT

      if (!next() || addr() >= begin) break;

    }

    assert(addrCheck == NULL || addrCheck == backup_addr, "must have matched addrCheck");

    assert(infoCheck == NULL || infoCheck == backup,      "must have matched infoCheck");

    // At this point, either we are at the first matching record,

    // or else there is no such record, and !has_current().

    // In either case, revert to the immediatly preceding state.

    _current = backup;

    _addr    = backup_addr;

    set_has_current(false);

  }

}

void RelocIterator::set_limit(address limit) {

  address code_end = (address)code() + code()->size();

  assert(limit == NULL || limit <= code_end, "in bounds");

  _limit = limit;

}

void PatchingRelocIterator:: prepass() {

  // turn breakpoints off during patching

  _init_state = (*this);        // save cursor

  while (next()) {

    if (type() == relocInfo::breakpoint_type) {

      breakpoint_reloc()->set_active(false);

    }

  }

  (RelocIterator&)(*this) = _init_state;        // reset cursor for client

}

void PatchingRelocIterator:: postpass() {

  // turn breakpoints back on after patching

  (RelocIterator&)(*this) = _init_state;        // reset cursor again

  while (next()) {

    if (type() == relocInfo::breakpoint_type) {

      breakpoint_Relocation* bpt = breakpoint_reloc();

      bpt->set_active(bpt->enabled());

    }

  }

}

// All the strange bit-encodings are in here.

// The idea is to encode relocation data which are small integers

// very efficiently (a single extra halfword).  Larger chunks of

// relocation data need a halfword header to hold their size.

void RelocIterator::advance_over_prefix() {

  if (_current->is_datalen()) {

    _data    = (short*) _current->data();

    _datalen =          _current->datalen();

    _current += _datalen + 1;   // skip the embedded data & header

  } else {

    _databuf = _current->immediate();

    _data = &_databuf;

    _datalen = 1;

    _current++;                 // skip the header

  }

  // The client will see the following relocInfo, whatever that is.

  // It is the reloc to which the preceding data applies.

}

void RelocIterator::initialize_misc() {

  set_has_current(false);

  for (int i = (int) CodeBuffer::SECT_FIRST; i < (int) CodeBuffer::SECT_LIMIT; i++) {

    _section_start[i] = NULL;  // these will be lazily computed, if needed

    _section_end  [i] = NULL;

  }

}

Relocation* RelocIterator::reloc() {

  // (take the "switch" out-of-line)

  relocInfo::relocType t = type();

  if (false) {}

  #define EACH_TYPE(name)                             \

  else if (t == relocInfo::name##_type) {             \

    return name##_reloc();                            \

  }

  APPLY_TO_RELOCATIONS(EACH_TYPE);

  #undef EACH_TYPE

  assert(t == relocInfo::none, "must be padding");

  return new(_rh) Relocation();

}

//////// Methods for flyweight Relocation types

RelocationHolder RelocationHolder::plus(int offset) const {

  if (offset != 0) {

    switch (type()) {

    case relocInfo::none:

      break;

    case relocInfo::oop_type:

      {

        oop_Relocation* r = (oop_Relocation*)reloc();

        return oop_Relocation::spec(r->oop_index(), r->offset() + offset);

      }

    case relocInfo::metadata_type:

      {

        metadata_Relocation* r = (metadata_Relocation*)reloc();

        return metadata_Relocation::spec(r->metadata_index(), r->offset() + offset);

      }

    default:

      ShouldNotReachHere();

    }

  }

  return (*this);

}

void Relocation::guarantee_size() {

  guarantee(false, "Make _relocbuf bigger!");

}

    // some relocations can compute their own values

address Relocation::value() {

  ShouldNotReachHere();

  return NULL;

}

void Relocation::set_value(address x) {

  ShouldNotReachHere();

}

RelocationHolder Relocation::spec_simple(relocInfo::relocType rtype) {

  if (rtype == relocInfo::none)  return RelocationHolder::none;

  relocInfo ri = relocInfo(rtype, 0);

  RelocIterator itr;

  itr.set_current(ri);

  itr.reloc();

  return itr._rh;

}

int32_t Relocation::runtime_address_to_index(address runtime_address) {

  assert(!is_reloc_index((intptr_t)runtime_address), "must not look like an index");

  if (runtime_address == NULL)  return 0;

  StubCodeDesc* p = StubCodeDesc::desc_for(runtime_address);

  if (p != NULL && p->begin() == runtime_address) {

    assert(is_reloc_index(p->index()), "there must not be too many stubs");

    return (int32_t)p->index();

  } else {

    // Known "miscellaneous" non-stub pointers:

    // os::get_polling_page(), SafepointSynchronize::address_of_state()

    if (PrintRelocations) {

      tty->print_cr("random unregistered address in relocInfo: " INTPTR_FORMAT, runtime_address);

    }

#ifndef _LP64

    return (int32_t) (intptr_t)runtime_address;

#else

    // didn't fit return non-index

    return -1;

#endif /* _LP64 */

  }

}

address Relocation::index_to_runtime_address(int32_t index) {

  if (index == 0)  return NULL;

  if (is_reloc_index(index)) {

    StubCodeDesc* p = StubCodeDesc::desc_for_index(index);

    assert(p != NULL, "there must be a stub for this index");

    return p->begin();

  } else {

#ifndef _LP64

    // this only works on 32bit machines

    return (address) ((intptr_t) index);

#else

    fatal("Relocation::index_to_runtime_address, int32_t not pointer sized");

    return NULL;

#endif /* _LP64 */

  }

}

address Relocation::old_addr_for(address newa,

                                 const CodeBuffer* src, CodeBuffer* dest) {

  int sect = dest->section_index_of(newa);

  guarantee(sect != CodeBuffer::SECT_NONE, "lost track of this address");

  address ostart = src->code_section(sect)->start();

  address nstart = dest->code_section(sect)->start();

  return ostart + (newa - nstart);

}

address Relocation::new_addr_for(address olda,

                                 const CodeBuffer* src, CodeBuffer* dest) {

  debug_only(const CodeBuffer* src0 = src);

  int sect = CodeBuffer::SECT_NONE;

  // Look for olda in the source buffer, and all previous incarnations

  // if the source buffer has been expanded.

  for (; src != NULL; src = src->before_expand()) {

    sect = src->section_index_of(olda);

    if (sect != CodeBuffer::SECT_NONE)  break;

  }