/* vim: set ts=4 sw=4 tw=99 et:

  *

  * Copyright (C) 2012 David Anderson

  *

  * This file is part of JITCraft.

  *

  * JITCraft is free software: you can redistribute it and/or modify it under

  * the terms of the GNU General Public License as published by the Free

  * Software Foundation, either version 3 of the License, or (at your option)

  * any later version.

  * 

  * Foobar 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 for more details.

  *

  * You should have received a copy of the GNU General Public License along with

  * JITCraft. If not, see http://www.gnu.org/licenses/.

  */

 #include <string.h>

 #include "Zone.h"

 #include "Spaces.h"

 #include "Platform.h"

 #include "Spaces-inl.h"

 #include "Heap-inl.h"

 using namespace ke;

 HeapStack::HeapStack()

   : chunk_(NULL),

     cursor_(NULL)

 {

 }

 HeapStack::~HeapStack()

 {

     if (chunk_)

         HeapChunk::Destroy(chunk_);

 }

 bool

 HeapStack::initialize()

 {

     chunk_ = HeapChunk::New(NULL, kStackSize);

     cursor_ = chunk_->first();

     return true;

 }

 HeapChunk *

 HeapChunk::New(HeapChunk *prev, size_t size)

 {

     OS::AlignableMapping map = 

         OS::MapAlignedMemory(size, HeapChunk::kAlignment, OS::Map_Commit);

     if (!map.base())

         return NULL;

     HeapChunk *chunk = reinterpret_cast<HeapChunk *>(map.aligned());

     chunk->base_ = map.base();

     chunk->end_ = map.base() + map.size();

     if (prev)

         prev->next_ = chunk;

     return chunk;

 }

 void

 HeapChunk::Destroy(HeapChunk *chunk)

 {

     OS::UnmapAlignedMemory(chunk->base(), chunk->size());

 }

 void

 HeapChunk::resetMarkBits()

 {

     memset(markBits(), 0, kMarkBytes);

 }

 FreeList::FreeList()

   : small_objects_(NULL),

     medium_objects_(NULL),

     large_objects_(NULL),

     huge_objects_(NULL)

 {

 }

 void

 FreeList::add(FreedObject *obj)

 {

     if (obj->size() < kMinObjectSize) 

         return;

     FreedObject **list;

     if (obj->size() < kMaxSmallObject)

         list = &small_objects_;

     else if (obj->size() < kMaxMediumObject)

         list = &medium_objects_;

     else if (obj->size() < kMaxLargeObject)

         list = &large_objects_;

     else

         list = &huge_objects_;

     if (*list)

         (*list)->setNext(obj);

     *list = obj;

 }

 FreedObject *

 FreeList::pick(size_t size)

 {

     if (size < kMinObjectSize && small_objects_) {

         FreedObject *obj = small_objects_;

         small_objects_ = small_objects_->next();

         return obj;

     }

     if (size < kMaxSmallObject && medium_objects_) {

         FreedObject *obj = medium_objects_;

         medium_objects_ = medium_objects_->next();

         return obj;

     }

     if (size < kMaxMediumObject && large_objects_) {

         FreedObject *obj = large_objects_;

         large_objects_ = large_objects_->next();

         return obj;

     }

     if (huge_objects_) {

         FreedObject *obj = huge_objects_;

         huge_objects_ = huge_objects_->next();

         return obj;

     }

     return NULL;

 }

 void

 FreeList::reset()

 {

     small_objects_ = NULL;

     medium_objects_ = NULL;

     large_objects_ = NULL;

     huge_objects_ = NULL;

 }

 OldSpace::OldSpace(Zone *zone)

   : zone_(zone),

     first_(NULL),

     last_(NULL)

 {

 }

 bool

 OldSpace::initialize()

 {

     first_ = HeapChunk::New(first_, HeapChunk::kDefaultSize);

     last_ = first_;

     cursor_ = first_->first();

     return !!first_;

 }

 OldSpace::~OldSpace()

 {

     while (first_) {

         HeapChunk *temp = first_->next();

         HeapChunk::Destroy(first_);

         first_ = temp;

     }

 }

 Address

 OldSpace::allocateSlow(size_t nbytes)

 {

     if (FreedObject *obj = freelist_.pick(nbytes)) {

         Address address = reinterpret_cast<Address>(obj);

         size_t actual = obj->size();

         assert(actual >= nbytes);

         if (actual != nbytes)

             markRegionFree(address + nbytes, actual - nbytes);

         return address;

     }

     // Free unused stuff at the end of the current chunk.

     if (cursor_ != last_->end())

         markRegionFree(cursor_, last_->end() - cursor_);

     HeapChunk *chunk;

     if (last_->next()) {

         // The next chunk is guaranteed to be empty.

         chunk = last_->next();

     } else {

         chunk = HeapChunk::New(last_, HeapChunk::kDefaultSize);

         if (!chunk)

             return NULL;

     }

     last_ = chunk;

     cursor_ = chunk->first();

     assert(cursor_ + nbytes <= chunk->end());

     Address address = cursor_;

     cursor_ += nbytes;

     return address;

 }

 void

 OldSpace::markRegionFree(Address start, size_t length)

 {

     FreedObject *obj = reinterpret_cast<FreedObject *>(start);

     new (obj) FreedObject(zone_->getMap(MapKind_FreeRegion), length);

     if (length < sizeof(FreedObject)) {

         // Can't encode a list in this object, but it's marked free, so we're done.

         return;

     }

     freelist_.add(obj);

 }

 void

 OldSpace::freeUnusedPages()

 {

     HeapChunk **prev = &first_;

     HeapChunk *empty = NULL;

     while (*prev) {

         HeapChunk *chunk = *prev;

         if (chunk->isEmpty()) {

             *prev = chunk->next();

             if (empty) {

                 // Remove this chunk.

                 HeapChunk::Destroy(chunk);

                 continue;

             }

             empty = chunk;                

         }

         prev = chunk->nextp();

     }

     if (empty) {

         *empty->nextp() = NULL;

         *last_->nextp() = empty;

     }

 }

 void

 OldSpace::resetFreeList()

 {

     freelist_.reset();

 }

 LargeObjectSpace::LargeObjectSpace()

   : first_(NULL),

     last_(NULL)

 {

 }

 LargeObjectSpace::~LargeObjectSpace()

 {

     while (first_) {

         HeapChunk *temp = first_->next();

         HeapChunk::Destroy(first_);

         first_ = temp;

     }

 }

 bool

 LargeObjectSpace::initialize()

 {

     return true;

 }

 Address

 LargeObjectSpace::allocate(size_t nbytes)

 {

     assert(IsAligned(nbytes, kObjectAlignment));

     // Always allocate a new chunk for large objects.

     HeapChunk *chunk = HeapChunk::New(last_, nbytes);

     if (!chunk)

         return NULL;

     if (!first_)

         first_ = chunk;

     last_ = chunk;

     return chunk->first();

 }

 void

 LargeObjectSpace::sweep()

 {

     if (!first_)

         return;

     HeapChunk **pprev = &first_;

     do {

         HeapChunk *chunk = *pprev;

         Object *obj = reinterpret_cast<Object *>(chunk->first());

         MarkBit bit = HeapChunk::GetMarkBit(obj);

         if (HeapChunk::IsWhite(bit)) {

             *pprev = chunk->next();

             HeapChunk::Destroy(chunk);

         } else {

             assert(HeapChunk::IsBlack(bit));

             HeapChunk::Clear(bit);

             pprev = chunk->nextp();

             last_ = chunk;

         }

     } while (*pprev);

 }