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// Copyright 2018 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_EMBEDDED_DATA_H_
#define V8_SNAPSHOT_EMBEDDED_DATA_H_
#include "src/base/macros.h"
#include "src/builtins/builtins.h"
#include "src/common/globals.h"
#include "src/execution/isolate.h"
namespace v8 {
namespace internal {
class Code;
class Isolate;
// Wraps an off-heap instruction stream.
// TODO(jgruber,v8:6666): Remove this class.
class InstructionStream final : public AllStatic {
public:
// Returns true, iff the given pc points into an off-heap instruction stream.
static bool PcIsOffHeap(Isolate* isolate, Address pc);
// Returns the corresponding Code object if it exists, and nullptr otherwise.
static Code TryLookupCode(Isolate* isolate, Address address);
// During snapshot creation, we first create an executable off-heap area
// containing all off-heap code. The area is guaranteed to be contiguous.
// Note that this only applies when building the snapshot, e.g. for
// mksnapshot. Otherwise, off-heap code is embedded directly into the binary.
static void CreateOffHeapInstructionStream(Isolate* isolate, uint8_t** data,
uint32_t* size);
static void FreeOffHeapInstructionStream(uint8_t* data, uint32_t size);
};
class EmbeddedData final {
public:
static EmbeddedData FromIsolate(Isolate* isolate);
static EmbeddedData FromBlob() {
return EmbeddedData(Isolate::CurrentEmbeddedBlob(),
Isolate::CurrentEmbeddedBlobSize());
}
static EmbeddedData FromBlob(Isolate* isolate) {
return EmbeddedData(isolate->embedded_blob(),
isolate->embedded_blob_size());
}
const uint8_t* data() const { return data_; }
uint32_t size() const { return size_; }
void Dispose() { delete[] data_; }
Address InstructionStartOfBuiltin(int i) const;
uint32_t InstructionSizeOfBuiltin(int i) const;
Address InstructionStartOfBytecodeHandlers() const;
Address InstructionEndOfBytecodeHandlers() const;
bool ContainsBuiltin(int i) const { return InstructionSizeOfBuiltin(i) > 0; }
uint32_t AddressForHashing(Address addr) {
Address start = reinterpret_cast<Address>(data_);
DCHECK(IsInRange(addr, start, start + size_));
return static_cast<uint32_t>(addr - start);
}
// Padded with kCodeAlignment.
uint32_t PaddedInstructionSizeOfBuiltin(int i) const {
uint32_t size = InstructionSizeOfBuiltin(i);
return (size == 0) ? 0 : PadAndAlign(size);
}
size_t CreateEmbeddedBlobHash() const;
size_t EmbeddedBlobHash() const {
return *reinterpret_cast<const size_t*>(data_ + EmbeddedBlobHashOffset());
}
size_t IsolateHash() const {
return *reinterpret_cast<const size_t*>(data_ + IsolateHashOffset());
}
struct Metadata {
// Blob layout information.
uint32_t instructions_offset;
uint32_t instructions_length;
};
STATIC_ASSERT(offsetof(Metadata, instructions_offset) == 0);
STATIC_ASSERT(offsetof(Metadata, instructions_length) == kUInt32Size);
STATIC_ASSERT(sizeof(Metadata) == kUInt32Size + kUInt32Size);
// The layout of the blob is as follows:
//
// [0] hash of the remaining blob
// [1] hash of embedded-blob-relevant heap objects
// [2] metadata of instruction stream 0
// ... metadata
// ... instruction streams
static constexpr uint32_t kTableSize = Builtins::builtin_count;
static constexpr uint32_t EmbeddedBlobHashOffset() { return 0; }
static constexpr uint32_t EmbeddedBlobHashSize() { return kSizetSize; }
static constexpr uint32_t IsolateHashOffset() {
return EmbeddedBlobHashOffset() + EmbeddedBlobHashSize();
}
static constexpr uint32_t IsolateHashSize() { return kSizetSize; }
static constexpr uint32_t MetadataOffset() {
return IsolateHashOffset() + IsolateHashSize();
}
static constexpr uint32_t MetadataSize() {
return sizeof(struct Metadata) * kTableSize;
}
static constexpr uint32_t RawDataOffset() {
return PadAndAlign(MetadataOffset() + MetadataSize());
}
private:
EmbeddedData(const uint8_t* data, uint32_t size) : data_(data), size_(size) {
DCHECK_NOT_NULL(data);
DCHECK_LT(0, size);
}
const Metadata* Metadata() const {
return reinterpret_cast<const struct Metadata*>(data_ + MetadataOffset());
}
const uint8_t* RawData() const { return data_ + RawDataOffset(); }
static constexpr int PadAndAlign(int size) {
// Ensure we have at least one byte trailing the actual builtin
// instructions which we can later fill with int3.
return RoundUp<kCodeAlignment>(size + 1);
}
void PrintStatistics() const;
const uint8_t* data_;
uint32_t size_;
};
} // namespace internal
} // namespace v8
#endif // V8_SNAPSHOT_EMBEDDED_DATA_H_