Rename write buffers to store buffers.

src/write-buffer.cc

-// Copyright 2010 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.
-
-#include "v8-counters.h"
-#include "write-buffer.h"
-#include "write-buffer-inl.h"
-
-namespace v8 {
-namespace internal {
-
-Address* WriteBuffer::start_ = NULL;
-Address* WriteBuffer::limit_ = NULL;
-uintptr_t* WriteBuffer::hash_map_1_ = NULL;
-uintptr_t* WriteBuffer::hash_map_2_ = NULL;
-VirtualMemory* WriteBuffer::virtual_memory_ = NULL;
-
-void WriteBuffer::Setup() {
-  virtual_memory_ = new VirtualMemory(kWriteBufferSize * 3);
-  uintptr_t start_as_int =
-      reinterpret_cast<uintptr_t>(virtual_memory_->address());
-  start_ =
-      reinterpret_cast<Address*>(RoundUp(start_as_int, kWriteBufferSize * 2));
-  limit_ = start_ + (kWriteBufferSize / sizeof(*start_));
-
-  ASSERT(reinterpret_cast<Address>(start_) >= virtual_memory_->address());
-  ASSERT(reinterpret_cast<Address>(limit_) >= virtual_memory_->address());
-  Address* vm_limit = reinterpret_cast<Address*>(
-      reinterpret_cast<char*>(virtual_memory_->address()) +
-          virtual_memory_->size());
-  ASSERT(start_ <= vm_limit);
-  ASSERT(limit_ <= vm_limit);
-  USE(vm_limit);
-  ASSERT((reinterpret_cast<uintptr_t>(limit_) & kWriteBufferOverflowBit) != 0);
-  ASSERT((reinterpret_cast<uintptr_t>(limit_ - 1) & kWriteBufferOverflowBit) ==
-         0);
-
-  virtual_memory_->Commit(reinterpret_cast<Address>(start_),
-                          kWriteBufferSize,
-                          false);  // Not executable.
-  Heap::public_set_write_buffer_top(start_);
-
-  hash_map_1_ = new uintptr_t[kHashMapLength];
-  hash_map_2_ = new uintptr_t[kHashMapLength];
-}
-
-
-void WriteBuffer::TearDown() {
-  delete virtual_memory_;
-  delete[] hash_map_1_;
-  delete[] hash_map_2_;
-  start_ = limit_ = NULL;
-  Heap::public_set_write_buffer_top(start_);
-}
-
-
-void WriteBuffer::Compact() {
-  memset(reinterpret_cast<void*>(hash_map_1_),
-         0,
-         sizeof(uintptr_t) * kHashMapLength);
-  memset(reinterpret_cast<void*>(hash_map_2_),
-         0,
-         sizeof(uintptr_t) * kHashMapLength);
-  Address* top = reinterpret_cast<Address*>(Heap::write_buffer_top());
-  Address* stop = top;
-  ASSERT(top <= limit_);
-  top = start_;
-  // Goes through the addresses in the write buffer attempting to remove
-  // duplicates.  In the interest of speed this is a lossy operation.  Some
-  // duplicates will remain.  We have two hash tables with different hash
-  // functions to reduce the number of unnecessary clashes.
-  for (Address* current = start_; current < stop; current++) {
-    uintptr_t int_addr = reinterpret_cast<uintptr_t>(*current);
-    // Shift out the last bits including any tags.
-    int_addr >>= kPointerSizeLog2;
-    int hash1 =
-        ((int_addr ^ (int_addr >> kHashMapLengthLog2)) & (kHashMapLength - 1));
-    if (hash_map_1_[hash1] == int_addr) continue;
-    int hash2 =
-        ((int_addr - (int_addr >> kHashMapLengthLog2)) & (kHashMapLength - 1));
-    hash2 ^= hash2 >> (kHashMapLengthLog2 * 2);
-    if (hash_map_2_[hash2] == int_addr) continue;
-    if (hash_map_1_[hash1] == 0) {
-      hash_map_1_[hash1] = int_addr;
-    } else if (hash_map_2_[hash2] == 0) {
-      hash_map_2_[hash2] = int_addr;
-    } else {
-      // Rather than slowing down we just throw away some entries.  This will
-      // cause some duplicates to remain undetected.
-      hash_map_1_[hash1] = int_addr;
-      hash_map_2_[hash2] = 0;
-    }
-    ASSERT(top <= current);
-    ASSERT(top <= limit_);
-    *top++ = reinterpret_cast<Address>(int_addr << kPointerSizeLog2);
-  }
-  Counters::write_buffer_compactions.Increment();
-  if (limit_ - top < top - start_) {
-    // Compression did not free up at least half.
-    // TODO(gc): Set an interrupt to do a GC on the next back edge.
-    // TODO(gc): Allocate the rest of new space to force a GC on the next
-    // allocation.
-    if (limit_ - top < (top - start_) >> 1) {
-      // Compression did not free up at least one quarter.
-      // TODO(gc): Set a flag to scan all of memory.
-      top = start_;
-      Counters::write_buffer_overflows.Increment();
-    }
-  }
-  Heap::public_set_write_buffer_top(top);
-}
-
-} }  // namespace v8::internal