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// Copyright 2017 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef V8_SNAPSHOT_BUILTIN_DESERIALIZER_H_
#define V8_SNAPSHOT_BUILTIN_DESERIALIZER_H_
#include "src/interpreter/interpreter.h"
#include "src/snapshot/builtin-deserializer-allocator.h"
#include "src/snapshot/builtin-snapshot-utils.h"
#include "src/snapshot/deserializer.h"
namespace v8 {
namespace internal {
class BuiltinSnapshotData;
// Deserializes the builtins blob.
class BuiltinDeserializer final
: public Deserializer<BuiltinDeserializerAllocator> {
using BSU = BuiltinSnapshotUtils;
using Bytecode = interpreter::Bytecode;
using OperandScale = interpreter::OperandScale;
public:
BuiltinDeserializer(Isolate* isolate, const BuiltinSnapshotData* data);
// Builtins deserialization is tightly integrated with deserialization of the
// startup blob. In particular, we need to ensure that no GC can occur
// between startup- and builtins deserialization, as all builtins have been
// pre-allocated and their pointers may not be invalidated.
//
// After this, the instruction cache must be flushed by the caller (we don't
// do it ourselves since the startup serializer batch-flushes all code pages).
void DeserializeEagerBuiltinsAndHandlers();
// Deserializes the single given builtin. This is used whenever a builtin is
// lazily deserialized at runtime.
Code* DeserializeBuiltin(int builtin_id);
// Deserializes the single given handler. This is used whenever a handler is
// lazily deserialized at runtime.
Code* DeserializeHandler(Bytecode bytecode, OperandScale operand_scale);
private:
// Deserializes the single given builtin. Assumes that reservations have
// already been allocated.
Code* DeserializeBuiltinRaw(int builtin_id);
// Deserializes the single given bytecode handler. Assumes that reservations
// have already been allocated.
Code* DeserializeHandlerRaw(Bytecode bytecode, OperandScale operand_scale);
// Extracts the size builtin Code objects (baked into the snapshot).
uint32_t ExtractCodeObjectSize(int builtin_id);
// BuiltinDeserializer implements its own builtin iteration logic. Make sure
// the RootVisitor API is not used accidentally.
void VisitRootPointers(Root root, const char* description, Object** start,
Object** end) override {
UNREACHABLE();
}
int CurrentCodeObjectId() const { return current_code_object_id_; }
// Convenience function to grab the handler off the heap's strong root list.
Code* GetDeserializeLazyHandler(OperandScale operand_scale) const;
private:
// Stores the code object currently being deserialized. The
// {current_code_object_id} stores the index of the currently-deserialized
// code object within the snapshot (and within {code_offsets_}). We need this
// to determine where to 'allocate' from during deserialization.
static const int kNoCodeObjectId = -1;
int current_code_object_id_ = kNoCodeObjectId;
// The offsets of each builtin within the serialized data. Equivalent to
// BuiltinSerializer::builtin_offsets_ but on the deserialization side.
Vector<const uint32_t> code_offsets_;
// For current_code_object_id_.
friend class DeserializingCodeObjectScope;
// For isolate(), IsLazyDeserializationEnabled(), CurrentCodeObjectId() and
// ExtractBuiltinSize().
friend class BuiltinDeserializerAllocator;
};
} // namespace internal
} // namespace v8
#endif // V8_SNAPSHOT_BUILTIN_DESERIALIZER_H_