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// Copyright (c) 2012, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#ifndef VM_STORE_BUFFER_H_
#define VM_STORE_BUFFER_H_
#include "platform/assert.h"
#include "vm/globals.h"
#include "vm/hash_set.h"
namespace dart {
// Forward declarations.
class Isolate;
class StoreBufferBlock {
public:
// Each block contains kSize pointers.
static const int32_t kSize = 1024;
StoreBufferBlock() : top_(0) {}
static int top_offset() { return OFFSET_OF(StoreBufferBlock, top_); }
static int pointers_offset() {
return OFFSET_OF(StoreBufferBlock, pointers_);
}
void Reset() { top_ = 0; }
intptr_t Count() const { return top_; }
uword At(intptr_t i) const {
ASSERT(i >= 0);
ASSERT(i < top_);
return pointers_[i];
}
// Add a pointer to the block of pointers. The buffer will be processed if it
// has been filled by this operation.
void AddPointer(uword pointer) {
ASSERT(top_ < kSize);
pointers_[top_++] = pointer;
if (top_ == kSize) {
ProcessBuffer();
}
}
// Process this store buffer and remember its contents in the heap.
void ProcessBuffer();
void ProcessBuffer(Isolate* isolate);
bool Contains(uword pointer);
private:
int32_t top_;
uword pointers_[kSize];
friend class StoreBuffer;
DISALLOW_COPY_AND_ASSIGN(StoreBufferBlock);
};
class StoreBuffer {
public:
// Simple linked list element containing a HashSet of old->new pointers.
class DedupSet {
public:
enum {
kSetSize = 1024,
kFillRatio = 75
};
explicit DedupSet(DedupSet* next)
: next_(next), set_(new HashSet(kSetSize, kFillRatio)) {}
~DedupSet() {
delete set_;
}
DedupSet* next() const { return next_; }
HashSet* set() const { return set_; }
private:
DedupSet* next_;
HashSet* set_;
DISALLOW_COPY_AND_ASSIGN(DedupSet);
};
StoreBuffer() : dedup_sets_(new DedupSet(NULL)), count_(1) {}
~StoreBuffer();
void Reset();
void AddPointer(uword address);
// Drain StoreBufferBlock into deduplication sets.
// Returns true if new sets were created.
bool DrainBlock(StoreBufferBlock* block);
// Drain StoreBufferBlock into deduplication sets.
// Schedule an interrupt if we run over the max number of deduplication sets.
void ProcessBlock(StoreBufferBlock* block);
DedupSet* DedupSets() {
DedupSet* result = dedup_sets_;
dedup_sets_ = new DedupSet(NULL);
count_ = 1;
return result;
}
private:
// Add pointer to deduplication sets. Returns true if the current set is full
// and a new set was created.
bool AddPointerInternal(uword address);
// Check if we run over the max number of deduplication sets.
// If we did schedule an interrupt.
void CheckThreshold();
DedupSet* dedup_sets_;
intptr_t count_;
DISALLOW_COPY_AND_ASSIGN(StoreBuffer);
};
} // namespace dart
#endif // VM_STORE_BUFFER_H_