Mercurial > jdk8-mips64-public > hotspot / file revision

 /*

  * 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;

   }

   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 nstart + (olda - ostart);

 }

 void Relocation::normalize_address(address& addr, const CodeSection* dest, bool allow_other_sections) {

   address addr0 = addr;

   if (addr0 == NULL || dest->allocates2(addr0))  return;

   CodeBuffer* cb = dest->outer();

   addr = new_addr_for(addr0, cb, cb);

   assert(allow_other_sections || dest->contains2(addr),

          "addr must be in required section");

 }

 void CallRelocation::set_destination(address x) {

   pd_set_call_destination(x);

 }

 void CallRelocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {

   // Usually a self-relative reference to an external routine.

   // On some platforms, the reference is absolute (not self-relative).

   // The enhanced use of pd_call_destination sorts this all out.

   address orig_addr = old_addr_for(addr(), src, dest);

   address callee    = pd_call_destination(orig_addr);

   // Reassert the callee address, this time in the new copy of the code.

   pd_set_call_destination(callee);

 }

 //// pack/unpack methods

 void oop_Relocation::pack_data_to(CodeSection* dest) {

   short* p = (short*) dest->locs_end();

   p = pack_2_ints_to(p, _oop_index, _offset);

   dest->set_locs_end((relocInfo*) p);

 }

 void oop_Relocation::unpack_data() {

   unpack_2_ints(_oop_index, _offset);

 }

 void metadata_Relocation::pack_data_to(CodeSection* dest) {

   short* p = (short*) dest->locs_end();

   p = pack_2_ints_to(p, _metadata_index, _offset);

   dest->set_locs_end((relocInfo*) p);

 }

 void metadata_Relocation::unpack_data() {

   unpack_2_ints(_metadata_index, _offset);

 }

 void virtual_call_Relocation::pack_data_to(CodeSection* dest) {

   short*  p     = (short*) dest->locs_end();

   address point =          dest->locs_point();

   normalize_address(_cached_value, dest);

   jint x0 = scaled_offset_null_special(_cached_value, point);

   p = pack_1_int_to(p, x0);

   dest->set_locs_end((relocInfo*) p);

 }

 void virtual_call_Relocation::unpack_data() {

   jint x0 = unpack_1_int();

   address point = addr();

   _cached_value = x0==0? NULL: address_from_scaled_offset(x0, point);

 }

 void static_stub_Relocation::pack_data_to(CodeSection* dest) {

   short* p = (short*) dest->locs_end();

   CodeSection* insts = dest->outer()->insts();

   normalize_address(_static_call, insts);

   p = pack_1_int_to(p, scaled_offset(_static_call, insts->start()));

   dest->set_locs_end((relocInfo*) p);

 }

 void static_stub_Relocation::unpack_data() {

   address base = binding()->section_start(CodeBuffer::SECT_INSTS);

   _static_call = address_from_scaled_offset(unpack_1_int(), base);

 }

 void external_word_Relocation::pack_data_to(CodeSection* dest) {

   short* p = (short*) dest->locs_end();

   int32_t index = runtime_address_to_index(_target);

 #ifndef _LP64

   p = pack_1_int_to(p, index);

 #else

   if (is_reloc_index(index)) {

     p = pack_2_ints_to(p, index, 0);

   } else {

     jlong t = (jlong) _target;

     int32_t lo = low(t);

     int32_t hi = high(t);

     p = pack_2_ints_to(p, lo, hi);

     DEBUG_ONLY(jlong t1 = jlong_from(hi, lo));

     assert(!is_reloc_index(t1) && (address) t1 == _target, "not symmetric");

   }

 #endif /* _LP64 */

   dest->set_locs_end((relocInfo*) p);

 }

 void external_word_Relocation::unpack_data() {

 #ifndef _LP64

   _target = index_to_runtime_address(unpack_1_int());

 #else

   int32_t lo, hi;

   unpack_2_ints(lo, hi);

   jlong t = jlong_from(hi, lo);;

   if (is_reloc_index(t)) {

     _target = index_to_runtime_address(t);

   } else {

     _target = (address) t;

   }

 #endif /* _LP64 */

 }

 void internal_word_Relocation::pack_data_to(CodeSection* dest) {

   short* p = (short*) dest->locs_end();

   normalize_address(_target, dest, true);

   // Check whether my target address is valid within this section.

   // If not, strengthen the relocation type to point to another section.

   int sindex = _section;

   if (sindex == CodeBuffer::SECT_NONE && _target != NULL

       && (!dest->allocates(_target) || _target == dest->locs_point())) {

     sindex = dest->outer()->section_index_of(_target);

     guarantee(sindex != CodeBuffer::SECT_NONE, "must belong somewhere");

     relocInfo* base = dest->locs_end() - 1;

     assert(base->type() == this->type(), "sanity");

     // Change the written type, to be section_word_type instead.

     base->set_type(relocInfo::section_word_type);

   }

   // Note: An internal_word relocation cannot refer to its own instruction,

   // because we reserve "0" to mean that the pointer itself is embedded

   // in the code stream.  We use a section_word relocation for such cases.

   if (sindex == CodeBuffer::SECT_NONE) {

     assert(type() == relocInfo::internal_word_type, "must be base class");

     guarantee(_target == NULL || dest->allocates2(_target), "must be within the given code section");

     jint x0 = scaled_offset_null_special(_target, dest->locs_point());

     assert(!(x0 == 0 && _target != NULL), "correct encoding of null target");

     p = pack_1_int_to(p, x0);

   } else {

     assert(_target != NULL, "sanity");

     CodeSection* sect = dest->outer()->code_section(sindex);

     guarantee(sect->allocates2(_target), "must be in correct section");

     address base = sect->start();

     jint offset = scaled_offset(_target, base);

     assert((uint)sindex < (uint)CodeBuffer::SECT_LIMIT, "sanity");

     assert(CodeBuffer::SECT_LIMIT <= (1 << section_width), "section_width++");

     p = pack_1_int_to(p, (offset << section_width) | sindex);

   }

   dest->set_locs_end((relocInfo*) p);

 }

 void internal_word_Relocation::unpack_data() {

   jint x0 = unpack_1_int();

   _target = x0==0? NULL: address_from_scaled_offset(x0, addr());

   _section = CodeBuffer::SECT_NONE;

 }

 void section_word_Relocation::unpack_data() {

   jint    x      = unpack_1_int();

   jint    offset = (x >> section_width);

   int     sindex = (x & ((1<<section_width)-1));

   address base   = binding()->section_start(sindex);

   _section = sindex;

   _target  = address_from_scaled_offset(offset, base);

 }

 void breakpoint_Relocation::pack_data_to(CodeSection* dest) {

   short* p = (short*) dest->locs_end();

   address point = dest->locs_point();

   *p++ = _bits;

   assert(_target != NULL, "sanity");

   if (internal())  normalize_address(_target, dest);

   jint target_bits =

     (jint)( internal() ? scaled_offset           (_target, point)

                        : runtime_address_to_index(_target) );

   if (settable()) {

     // save space for set_target later

     p = add_jint(p, target_bits);

   } else {

     p = add_var_int(p, target_bits);

   }

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

     // put placeholder words until bytes can be saved

     p = add_short(p, (short)0x7777);

   }

   dest->set_locs_end((relocInfo*) p);

 }

 void breakpoint_Relocation::unpack_data() {

   _bits = live_bits();

   int targetlen = datalen() - 1 - instrlen();

   jint target_bits = 0;

   if (targetlen == 0)       target_bits = 0;

   else if (targetlen == 1)  target_bits = *(data()+1);

   else if (targetlen == 2)  target_bits = relocInfo::jint_from_data(data()+1);

   else                      { ShouldNotReachHere(); }

   _target = internal() ? address_from_scaled_offset(target_bits, addr())

                        : index_to_runtime_address  (target_bits);

 }

 //// miscellaneous methods

 oop* oop_Relocation::oop_addr() {

   int n = _oop_index;

   if (n == 0) {

     // oop is stored in the code stream

     return (oop*) pd_address_in_code();

   } else {

     // oop is stored in table at nmethod::oops_begin

     return code()->oop_addr_at(n);

   }

 }

 oop oop_Relocation::oop_value() {

   oop v = *oop_addr();

   // clean inline caches store a special pseudo-null

   if (v == (oop)Universe::non_oop_word())  v = NULL;

   return v;

 }

 void oop_Relocation::fix_oop_relocation() {

   if (!oop_is_immediate()) {

     // get the oop from the pool, and re-insert it into the instruction:

     set_value(value());

   }

 }

 void oop_Relocation::verify_oop_relocation() {

   if (!oop_is_immediate()) {

     // get the oop from the pool, and re-insert it into the instruction:

     verify_value(value());

   }

 }

 // meta data versions

 Metadata** metadata_Relocation::metadata_addr() {

   int n = _metadata_index;

   if (n == 0) {

     // metadata is stored in the code stream

     return (Metadata**) pd_address_in_code();

     } else {

     // metadata is stored in table at nmethod::metadatas_begin

     return code()->metadata_addr_at(n);

     }

   }

 Metadata* metadata_Relocation::metadata_value() {

   Metadata* v = *metadata_addr();

   // clean inline caches store a special pseudo-null

   if (v == (Metadata*)Universe::non_oop_word())  v = NULL;

   return v;

   }

 void metadata_Relocation::fix_metadata_relocation() {

   if (!metadata_is_immediate()) {

     // get the metadata from the pool, and re-insert it into the instruction:

     pd_fix_value(value());

   }

 }

 void metadata_Relocation::verify_metadata_relocation() {

   if (!metadata_is_immediate()) {

     // get the metadata from the pool, and re-insert it into the instruction:

     verify_value(value());

   }

 }

 address virtual_call_Relocation::cached_value() {

   assert(_cached_value != NULL && _cached_value < addr(), "must precede ic_call");

   return _cached_value;

 }

 void virtual_call_Relocation::clear_inline_cache() {

   // No stubs for ICs

   // Clean IC

   ResourceMark rm;

   CompiledIC* icache = CompiledIC_at(this);

   icache->set_to_clean();

 }

 void opt_virtual_call_Relocation::clear_inline_cache() {

   // No stubs for ICs

   // Clean IC

   ResourceMark rm;

   CompiledIC* icache = CompiledIC_at(this);

   icache->set_to_clean();

 }

 address opt_virtual_call_Relocation::static_stub() {

   // search for the static stub who points back to this static call

   address static_call_addr = addr();

   RelocIterator iter(code());

   while (iter.next()) {

     if (iter.type() == relocInfo::static_stub_type) {

       if (iter.static_stub_reloc()->static_call() == static_call_addr) {

         return iter.addr();

       }

     }

   }

   return NULL;

 }

 void static_call_Relocation::clear_inline_cache() {

   // Safe call site info

   CompiledStaticCall* handler = compiledStaticCall_at(this);

   handler->set_to_clean();

 }

 address static_call_Relocation::static_stub() {

   // search for the static stub who points back to this static call

   address static_call_addr = addr();

   RelocIterator iter(code());

   while (iter.next()) {

     if (iter.type() == relocInfo::static_stub_type) {

       if (iter.static_stub_reloc()->static_call() == static_call_addr) {

         return iter.addr();

       }

     }

   }

   return NULL;

 }

 void static_stub_Relocation::clear_inline_cache() {

   // Call stub is only used when calling the interpreted code.

   // It does not really need to be cleared, except that we want to clean out the methodoop.

   CompiledStaticCall::set_stub_to_clean(this);

 }

 void external_word_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {

   address target = _target;

   if (target == NULL) {

     // An absolute embedded reference to an external location,

     // which means there is nothing to fix here.

     return;

   }

   // Probably this reference is absolute, not relative, so the

   // following is probably a no-op.

   assert(src->section_index_of(target) == CodeBuffer::SECT_NONE, "sanity");

   set_value(target);

 }

 address external_word_Relocation::target() {

   address target = _target;

   if (target == NULL) {

     target = pd_get_address_from_code();

   }

   return target;

 }

 void internal_word_Relocation::fix_relocation_after_move(const CodeBuffer* src, CodeBuffer* dest) {

   address target = _target;

   if (target == NULL) {

     if (addr_in_const()) {

       target = new_addr_for(*(address*)addr(), src, dest);

     } else {

       target = new_addr_for(pd_get_address_from_code(), src, dest);

     }

   }

   set_value(target);

 }

 address internal_word_Relocation::target() {

   address target = _target;

   if (target == NULL) {

     target = pd_get_address_from_code();

   }

   return target;

 }

 breakpoint_Relocation::breakpoint_Relocation(int kind, address target, bool internal) {

   bool active    = false;

   bool enabled   = (kind == initialization);

   bool removable = (kind != safepoint);

   bool settable  = (target == NULL);

   int bits = kind;

   if (enabled)    bits |= enabled_state;

   if (internal)   bits |= internal_attr;

   if (removable)  bits |= removable_attr;

   if (settable)   bits |= settable_attr;

   _bits = bits | high_bit;

   _target = target;

   assert(this->kind()      == kind,      "kind encoded");

   assert(this->enabled()   == enabled,   "enabled encoded");

   assert(this->active()    == active,    "active encoded");

   assert(this->internal()  == internal,  "internal encoded");

   assert(this->removable() == removable, "removable encoded");

   assert(this->settable()  == settable,  "settable encoded");

 }

 address breakpoint_Relocation::target() const {

   return _target;

 }

 void breakpoint_Relocation::set_target(address x) {

   assert(settable(), "must be settable");

   jint target_bits =

     (jint)(internal() ? scaled_offset           (x, addr())

                       : runtime_address_to_index(x));

   short* p = &live_bits() + 1;

   p = add_jint(p, target_bits);

   assert(p == instrs(), "new target must fit");

   _target = x;

 }

 void breakpoint_Relocation::set_enabled(bool b) {

   if (enabled() == b) return;

   if (b) {

     set_bits(bits() | enabled_state);

   } else {

     set_active(false);          // remove the actual breakpoint insn, if any

     set_bits(bits() & ~enabled_state);

   }

 }

 void breakpoint_Relocation::set_active(bool b) {

   assert(!b || enabled(), "cannot activate a disabled breakpoint");

   if (active() == b) return;

   // %%% should probably seize a lock here (might not be the right lock)

   //MutexLockerEx ml_patch(Patching_lock, true);

   //if (active() == b)  return;         // recheck state after locking

   if (b) {

     set_bits(bits() | active_state);

     if (instrlen() == 0)

       fatal("breakpoints in original code must be undoable");

     pd_swap_in_breakpoint (addr(), instrs(), instrlen());

   } else {

     set_bits(bits() & ~active_state);

     pd_swap_out_breakpoint(addr(), instrs(), instrlen());

   }

 }

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

 // Non-product code

 #ifndef PRODUCT

 static const char* reloc_type_string(relocInfo::relocType t) {

   switch (t) {

   #define EACH_CASE(name) \

   case relocInfo::name##_type: \

     return #name;

   APPLY_TO_RELOCATIONS(EACH_CASE);

   #undef EACH_CASE

   case relocInfo::none:

     return "none";

   case relocInfo::data_prefix_tag:

     return "prefix";

   default:

     return "UNKNOWN RELOC TYPE";

   }

 }

 void RelocIterator::print_current() {

   if (!has_current()) {

     tty->print_cr("(no relocs)");

     return;

   }

   tty->print("relocInfo@" INTPTR_FORMAT " [type=%d(%s) addr=" INTPTR_FORMAT " offset=%d",

              _current, type(), reloc_type_string((relocInfo::relocType) type()), _addr, _current->addr_offset());

   if (current()->format() != 0)

     tty->print(" format=%d", current()->format());

   if (datalen() == 1) {

     tty->print(" data=%d", data()[0]);

   } else if (datalen() > 0) {

     tty->print(" data={");

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

       tty->print("%04x", data()[i] & 0xFFFF);

     }

     tty->print("}");

   }

   tty->print("]");

   switch (type()) {

   case relocInfo::oop_type:

     {

       oop_Relocation* r = oop_reloc();

       oop* oop_addr  = NULL;

       oop  raw_oop   = NULL;

       oop  oop_value = NULL;

       if (code() != NULL || r->oop_is_immediate()) {

         oop_addr  = r->oop_addr();

         raw_oop   = *oop_addr;

         oop_value = r->oop_value();

       }

       tty->print(" | [oop_addr=" INTPTR_FORMAT " *=" INTPTR_FORMAT " offset=%d]",

                  oop_addr, (address)raw_oop, r->offset());

       // Do not print the oop by default--we want this routine to

       // work even during GC or other inconvenient times.

       if (WizardMode && oop_value != NULL) {

         tty->print("oop_value=" INTPTR_FORMAT ": ", (address)oop_value);

         oop_value->print_value_on(tty);

       }

       break;

     }

   case relocInfo::metadata_type:

     {

       metadata_Relocation* r = metadata_reloc();

       Metadata** metadata_addr  = NULL;

       Metadata*    raw_metadata   = NULL;

       Metadata*    metadata_value = NULL;

       if (code() != NULL || r->metadata_is_immediate()) {

         metadata_addr  = r->metadata_addr();

         raw_metadata   = *metadata_addr;

         metadata_value = r->metadata_value();

       }

       tty->print(" | [metadata_addr=" INTPTR_FORMAT " *=" INTPTR_FORMAT " offset=%d]",

                  metadata_addr, (address)raw_metadata, r->offset());

       if (metadata_value != NULL) {

         tty->print("metadata_value=" INTPTR_FORMAT ": ", (address)metadata_value);

         metadata_value->print_value_on(tty);

       }

       break;

     }

   case relocInfo::external_word_type:

   case relocInfo::internal_word_type:

   case relocInfo::section_word_type:

     {

       DataRelocation* r = (DataRelocation*) reloc();

       tty->print(" | [target=" INTPTR_FORMAT "]", r->value()); //value==target

       break;

     }

   case relocInfo::static_call_type:

   case relocInfo::runtime_call_type:

     {

       CallRelocation* r = (CallRelocation*) reloc();

       tty->print(" | [destination=" INTPTR_FORMAT "]", r->destination());

       break;

     }

   case relocInfo::virtual_call_type:

     {

       virtual_call_Relocation* r = (virtual_call_Relocation*) reloc();

       tty->print(" | [destination=" INTPTR_FORMAT " cached_value=" INTPTR_FORMAT "]",

                  r->destination(), r->cached_value());

       break;

     }

   case relocInfo::static_stub_type:

     {

       static_stub_Relocation* r = (static_stub_Relocation*) reloc();

       tty->print(" | [static_call=" INTPTR_FORMAT "]", r->static_call());

       break;

     }

   }

   tty->cr();

 }

 void RelocIterator::print() {

   RelocIterator save_this = (*this);

   relocInfo* scan = _current;

   if (!has_current())  scan += 1;  // nothing to scan here!

   bool skip_next = has_current();

   bool got_next;

   while (true) {

     got_next = (skip_next || next());

     skip_next = false;

     tty->print("         @" INTPTR_FORMAT ": ", scan);

     relocInfo* newscan = _current+1;

     if (!has_current())  newscan -= 1;  // nothing to scan here!

     while (scan < newscan) {

       tty->print("%04x", *(short*)scan & 0xFFFF);

       scan++;

     }

     tty->cr();

     if (!got_next)  break;

     print_current();

   }

   (*this) = save_this;

 }

 // For the debugger:

 extern "C"

 void print_blob_locs(nmethod* nm) {

   nm->print();

   RelocIterator iter(nm);

   iter.print();

 }

 extern "C"

 void print_buf_locs(CodeBuffer* cb) {

   FlagSetting fs(PrintRelocations, true);

   cb->print();

 }

 #endif // !PRODUCT