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// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#ifndef V8_SPACES_INL_H_
#define V8_SPACES_INL_H_
#include "memory.h"
#include "spaces.h"
namespace v8 {
namespace internal {
// -----------------------------------------------------------------------------
// PageIterator
bool PageIterator::has_next() {
return prev_page_ != stop_page_;
}
Page* PageIterator::next() {
ASSERT(has_next());
prev_page_ = (prev_page_ == NULL)
? space_->first_page_
: prev_page_->next_page();
return prev_page_;
}
// -----------------------------------------------------------------------------
// Page
Page* Page::next_page() {
return MemoryAllocator::GetNextPage(this);
}
Address Page::AllocationTop() {
PagedSpace* owner = MemoryAllocator::PageOwner(this);
return owner->PageAllocationTop(this);
}
void Page::ClearRSet() {
// This method can be called in all rset states.
memset(RSetStart(), 0, kRSetEndOffset - kRSetStartOffset);
}
// Given a 32-bit address, separate its bits into:
// | page address | words (6) | bit offset (5) | pointer alignment (2) |
// The address of the rset word containing the bit for this word is computed as:
// page_address + words * 4
// For a 64-bit address, if it is:
// | page address | words(5) | bit offset(5) | pointer alignment (3) |
// The address of the rset word containing the bit for this word is computed as:
// page_address + words * 4 + kRSetOffset.
// The rset is accessed as 32-bit words, and bit offsets in a 32-bit word,
// even on the X64 architecture.
Address Page::ComputeRSetBitPosition(Address address, int offset,
uint32_t* bitmask) {
ASSERT(Page::is_rset_in_use());
Page* page = Page::FromAddress(address);
uint32_t bit_offset = ArithmeticShiftRight(page->Offset(address) + offset,
kPointerSizeLog2);
*bitmask = 1 << (bit_offset % kBitsPerInt);
Address rset_address =
page->address() + kRSetOffset + (bit_offset / kBitsPerInt) * kIntSize;
// The remembered set address is either in the normal remembered set range
// of a page or else we have a large object page.
ASSERT((page->RSetStart() <= rset_address && rset_address < page->RSetEnd())
|| page->IsLargeObjectPage());
if (rset_address >= page->RSetEnd()) {
// We have a large object page, and the remembered set address is actually
// past the end of the object.
// The first part of the remembered set is still located at the start of
// the page, but anything after kRSetEndOffset must be relocated to after
// the large object, i.e. after
// (page->ObjectAreaStart() + object size)
// We do that by adding the difference between the normal RSet's end and
// the object's end.
ASSERT(HeapObject::FromAddress(address)->IsFixedArray());
int fixedarray_length =
FixedArray::SizeFor(Memory::int_at(page->ObjectAreaStart()
+ Array::kLengthOffset));
rset_address += kObjectStartOffset - kRSetEndOffset + fixedarray_length;
}
return rset_address;
}
void Page::SetRSet(Address address, int offset) {
uint32_t bitmask = 0;
Address rset_address = ComputeRSetBitPosition(address, offset, &bitmask);
Memory::uint32_at(rset_address) |= bitmask;
ASSERT(IsRSetSet(address, offset));
}
// Clears the corresponding remembered set bit for a given address.
void Page::UnsetRSet(Address address, int offset) {
uint32_t bitmask = 0;
Address rset_address = ComputeRSetBitPosition(address, offset, &bitmask);
Memory::uint32_at(rset_address) &= ~bitmask;
ASSERT(!IsRSetSet(address, offset));
}
bool Page::IsRSetSet(Address address, int offset) {
uint32_t bitmask = 0;
Address rset_address = ComputeRSetBitPosition(address, offset, &bitmask);
return (Memory::uint32_at(rset_address) & bitmask) != 0;
}
// -----------------------------------------------------------------------------
// MemoryAllocator
bool MemoryAllocator::IsValidChunk(int chunk_id) {
if (!IsValidChunkId(chunk_id)) return false;
ChunkInfo& c = chunks_[chunk_id];
return (c.address() != NULL) && (c.size() != 0) && (c.owner() != NULL);
}
bool MemoryAllocator::IsValidChunkId(int chunk_id) {
return (0 <= chunk_id) && (chunk_id < max_nof_chunks_);
}
bool MemoryAllocator::IsPageInSpace(Page* p, PagedSpace* space) {
ASSERT(p->is_valid());
int chunk_id = GetChunkId(p);
if (!IsValidChunkId(chunk_id)) return false;
ChunkInfo& c = chunks_[chunk_id];
return (c.address() <= p->address()) &&
(p->address() < c.address() + c.size()) &&
(space == c.owner());
}
Page* MemoryAllocator::GetNextPage(Page* p) {
ASSERT(p->is_valid());
intptr_t raw_addr = p->opaque_header & ~Page::kPageAlignmentMask;
return Page::FromAddress(AddressFrom<Address>(raw_addr));
}
int MemoryAllocator::GetChunkId(Page* p) {
ASSERT(p->is_valid());
return p->opaque_header & Page::kPageAlignmentMask;
}
void MemoryAllocator::SetNextPage(Page* prev, Page* next) {
ASSERT(prev->is_valid());
int chunk_id = GetChunkId(prev);
ASSERT_PAGE_ALIGNED(next->address());
prev->opaque_header = OffsetFrom(next->address()) | chunk_id;
}
PagedSpace* MemoryAllocator::PageOwner(Page* page) {
int chunk_id = GetChunkId(page);
ASSERT(IsValidChunk(chunk_id));
return chunks_[chunk_id].owner();
}
bool MemoryAllocator::InInitialChunk(Address address) {
if (initial_chunk_ == NULL) return false;
Address start = static_cast<Address>(initial_chunk_->address());
return (start <= address) && (address < start + initial_chunk_->size());
}
#ifdef ENABLE_HEAP_PROTECTION
void MemoryAllocator::Protect(Address start, size_t size) {
OS::Protect(start, size);
}
void MemoryAllocator::Unprotect(Address start,
size_t size,
Executability executable) {
OS::Unprotect(start, size, executable);
}
void MemoryAllocator::ProtectChunkFromPage(Page* page) {
int id = GetChunkId(page);
OS::Protect(chunks_[id].address(), chunks_[id].size());
}
void MemoryAllocator::UnprotectChunkFromPage(Page* page) {
int id = GetChunkId(page);
OS::Unprotect(chunks_[id].address(), chunks_[id].size(),
chunks_[id].owner()->executable() == EXECUTABLE);
}
#endif
// --------------------------------------------------------------------------
// PagedSpace
bool PagedSpace::Contains(Address addr) {
Page* p = Page::FromAddress(addr);
ASSERT(p->is_valid());
return MemoryAllocator::IsPageInSpace(p, this);
}
// Try linear allocation in the page of alloc_info's allocation top. Does
// not contain slow case logic (eg, move to the next page or try free list
// allocation) so it can be used by all the allocation functions and for all
// the paged spaces.
HeapObject* PagedSpace::AllocateLinearly(AllocationInfo* alloc_info,
int size_in_bytes) {
Address current_top = alloc_info->top;
Address new_top = current_top + size_in_bytes;
if (new_top > alloc_info->limit) return NULL;
alloc_info->top = new_top;
ASSERT(alloc_info->VerifyPagedAllocation());
accounting_stats_.AllocateBytes(size_in_bytes);
return HeapObject::FromAddress(current_top);
}
// Raw allocation.
Object* PagedSpace::AllocateRaw(int size_in_bytes) {
ASSERT(HasBeenSetup());
ASSERT_OBJECT_SIZE(size_in_bytes);
HeapObject* object = AllocateLinearly(&allocation_info_, size_in_bytes);
if (object != NULL) return object;
object = SlowAllocateRaw(size_in_bytes);
if (object != NULL) return object;
return Failure::RetryAfterGC(size_in_bytes, identity());
}
// Reallocating (and promoting) objects during a compacting collection.
Object* PagedSpace::MCAllocateRaw(int size_in_bytes) {
ASSERT(HasBeenSetup());
ASSERT_OBJECT_SIZE(size_in_bytes);
HeapObject* object = AllocateLinearly(&mc_forwarding_info_, size_in_bytes);
if (object != NULL) return object;
object = SlowMCAllocateRaw(size_in_bytes);
if (object != NULL) return object;
return Failure::RetryAfterGC(size_in_bytes, identity());
}
// -----------------------------------------------------------------------------
// LargeObjectChunk
HeapObject* LargeObjectChunk::GetObject() {
// Round the chunk address up to the nearest page-aligned address
// and return the heap object in that page.
Page* page = Page::FromAddress(RoundUp(address(), Page::kPageSize));
return HeapObject::FromAddress(page->ObjectAreaStart());
}
// -----------------------------------------------------------------------------
// LargeObjectSpace
int LargeObjectSpace::ExtraRSetBytesFor(int object_size) {
int extra_rset_bits =
RoundUp((object_size - Page::kObjectAreaSize) / kPointerSize,
kBitsPerInt);
return extra_rset_bits / kBitsPerByte;
}
Object* NewSpace::AllocateRawInternal(int size_in_bytes,
AllocationInfo* alloc_info) {
Address new_top = alloc_info->top + size_in_bytes;
if (new_top > alloc_info->limit) return Failure::RetryAfterGC(size_in_bytes);
Object* obj = HeapObject::FromAddress(alloc_info->top);
alloc_info->top = new_top;
#ifdef DEBUG
SemiSpace* space =
(alloc_info == &allocation_info_) ? &to_space_ : &from_space_;
ASSERT(space->low() <= alloc_info->top
&& alloc_info->top <= space->high()
&& alloc_info->limit == space->high());
#endif
return obj;
}
bool FreeListNode::IsFreeListNode(HeapObject* object) {
return object->map() == Heap::raw_unchecked_byte_array_map()
|| object->map() == Heap::raw_unchecked_one_pointer_filler_map()
|| object->map() == Heap::raw_unchecked_two_pointer_filler_map();
}
} } // namespace v8::internal
#endif // V8_SPACES_INL_H_