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Commit cdb845b0 authored by Jakob Gruber's avatar Jakob Gruber Committed by Commit Bot
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[snapshot] Hide private parts of snapshot.h 

snapshot.h is intended to be the public header for the snapshot
component, and not the right place for private declarations. This moves
them into a new SnapshotImpl class in snapshot.cc (previously named
snapshot-common.cc).

Bug: v8:10416
Change-Id: If34ad8d6e189050686942488fb8e99c3d310beee
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2144062
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: 's avatarDan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67279}
parent eefd5d31
Hide whitespace changes
Inline Side-by-side
Showing with 131 additions and 117 deletions
BUILD.gn
View file @ cdb845b0
......@@ -2960,13 +2960,13 @@ v8_source_set("v8_base_without_compiler") {
"src/snapshot/serializer-common.h",
"src/snapshot/serializer.cc",
"src/snapshot/serializer.h",
"src/snapshot/snapshot-common.cc",
"src/snapshot/snapshot-compression.cc",
"src/snapshot/snapshot-compression.h",
"src/snapshot/snapshot-data.cc",
"src/snapshot/snapshot-data.h",
"src/snapshot/snapshot-source-sink.cc",
"src/snapshot/snapshot-source-sink.h",
"src/snapshot/snapshot.cc",
"src/snapshot/snapshot.h",
"src/snapshot/startup-deserializer.cc",
"src/snapshot/startup-deserializer.h",
......
src/snapshot/snapshot-common.cc → src/snapshot/snapshot.cc
View file @ cdb845b0
......@@ -21,6 +21,76 @@
namespace v8 {
namespace internal {
namespace {
class SnapshotImpl : public AllStatic {
public:
static uint32_t ExtractNumContexts(const v8::StartupData* data);
static uint32_t ExtractContextOffset(const v8::StartupData* data,
uint32_t index);
static Vector<const byte> ExtractStartupData(const v8::StartupData* data);
static Vector<const byte> ExtractReadOnlyData(const v8::StartupData* data);
static Vector<const byte> ExtractContextData(const v8::StartupData* data,
uint32_t index);
static uint32_t GetHeaderValue(const v8::StartupData* data, uint32_t offset) {
return base::ReadLittleEndianValue<uint32_t>(
reinterpret_cast<Address>(data->data) + offset);
}
static void SetHeaderValue(char* data, uint32_t offset, uint32_t value) {
base::WriteLittleEndianValue(reinterpret_cast<Address>(data) + offset,
value);
}
static void CheckVersion(const v8::StartupData* data);
// Snapshot blob layout:
// [0] number of contexts N
// [1] rehashability
// [2] checksum
// [3] (128 bytes) version string
// [4] offset to readonly
// [5] offset to context 0
// [6] offset to context 1
// ...
// ... offset to context N - 1
// ... startup snapshot data
// ... read-only snapshot data
// ... context 0 snapshot data
// ... context 1 snapshot data
static const uint32_t kNumberOfContextsOffset = 0;
// TODO(yangguo): generalize rehashing, and remove this flag.
static const uint32_t kRehashabilityOffset =
kNumberOfContextsOffset + kUInt32Size;
static const uint32_t kChecksumOffset = kRehashabilityOffset + kUInt32Size;
static const uint32_t kVersionStringOffset = kChecksumOffset + kUInt32Size;
static const uint32_t kVersionStringLength = 64;
static const uint32_t kReadOnlyOffsetOffset =
kVersionStringOffset + kVersionStringLength;
static const uint32_t kFirstContextOffsetOffset =
kReadOnlyOffsetOffset + kUInt32Size;
static Vector<const byte> ChecksummedContent(const v8::StartupData* data) {
STATIC_ASSERT(kVersionStringOffset == kChecksumOffset + kUInt32Size);
const uint32_t kChecksumStart = kVersionStringOffset;
return Vector<const byte>(
reinterpret_cast<const byte*>(data->data + kChecksumStart),
data->raw_size - kChecksumStart);
}
static uint32_t StartupSnapshotOffset(int num_contexts) {
return POINTER_SIZE_ALIGN(kFirstContextOffsetOffset +
num_contexts * kInt32Size);
}
static uint32_t ContextSnapshotOffsetOffset(int index) {
return kFirstContextOffsetOffset + index * kInt32Size;
}
};
} // namespace
SnapshotData MaybeDecompress(const Vector<const byte>& snapshot_data) {
#ifdef V8_SNAPSHOT_COMPRESSION
return SnapshotCompression::Decompress(snapshot_data);
......@@ -31,7 +101,7 @@ SnapshotData MaybeDecompress(const Vector<const byte>& snapshot_data) {
#ifdef DEBUG
bool Snapshot::SnapshotIsValid(const v8::StartupData* snapshot_blob) {
return Snapshot::ExtractNumContexts(snapshot_blob) > 0;
return SnapshotImpl::ExtractNumContexts(snapshot_blob) > 0;
}
#endif // DEBUG
......@@ -40,7 +110,8 @@ bool Snapshot::HasContextSnapshot(Isolate* isolate, size_t index) {
const v8::StartupData* blob = isolate->snapshot_blob();
if (blob == nullptr) return false;
if (blob->data == nullptr) return false;
size_t num_contexts = static_cast<size_t>(ExtractNumContexts(blob));
size_t num_contexts =
static_cast<size_t>(SnapshotImpl::ExtractNumContexts(blob));
return index < num_contexts;
}
......@@ -52,10 +123,10 @@ bool Snapshot::Initialize(Isolate* isolate) {
if (FLAG_profile_deserialization) timer.Start();
const v8::StartupData* blob = isolate->snapshot_blob();
CheckVersion(blob);
SnapshotImpl::CheckVersion(blob);
CHECK(VerifyChecksum(blob));
Vector<const byte> startup_data = ExtractStartupData(blob);
Vector<const byte> read_only_data = ExtractReadOnlyData(blob);
Vector<const byte> startup_data = SnapshotImpl::ExtractStartupData(blob);
Vector<const byte> read_only_data = SnapshotImpl::ExtractReadOnlyData(blob);
SnapshotData startup_snapshot_data(MaybeDecompress(startup_data));
SnapshotData read_only_snapshot_data(MaybeDecompress(read_only_data));
......@@ -85,8 +156,8 @@ MaybeHandle<Context> Snapshot::NewContextFromSnapshot(
const v8::StartupData* blob = isolate->snapshot_blob();
bool can_rehash = ExtractRehashability(blob);
Vector<const byte> context_data =
ExtractContextData(blob, static_cast<uint32_t>(context_index));
Vector<const byte> context_data = SnapshotImpl::ExtractContextData(
blob, static_cast<uint32_t>(context_index));
SnapshotData snapshot_data(MaybeDecompress(context_data));
MaybeHandle<Context> maybe_result = PartialDeserializer::DeserializeContext(
......@@ -163,7 +234,8 @@ v8::StartupData Snapshot::CreateSnapshotBlob(
#endif
uint32_t num_contexts = static_cast<uint32_t>(context_snapshots->size());
uint32_t startup_snapshot_offset = StartupSnapshotOffset(num_contexts);
uint32_t startup_snapshot_offset =
SnapshotImpl::StartupSnapshotOffset(num_contexts);
uint32_t total_length = startup_snapshot_offset;
total_length += static_cast<uint32_t>(startup_snapshot->RawData().length());
total_length += static_cast<uint32_t>(read_only_snapshot->RawData().length());
......@@ -176,15 +248,18 @@ v8::StartupData Snapshot::CreateSnapshotBlob(
char* data = new char[total_length];
// Zero out pre-payload data. Part of that is only used for padding.
memset(data, 0, StartupSnapshotOffset(num_contexts));
memset(data, 0, SnapshotImpl::StartupSnapshotOffset(num_contexts));
SetHeaderValue(data, kNumberOfContextsOffset, num_contexts);
SetHeaderValue(data, kRehashabilityOffset, can_be_rehashed ? 1 : 0);
SnapshotImpl::SetHeaderValue(data, SnapshotImpl::kNumberOfContextsOffset,
num_contexts);
SnapshotImpl::SetHeaderValue(data, SnapshotImpl::kRehashabilityOffset,
can_be_rehashed ? 1 : 0);
// Write version string into snapshot data.
memset(data + kVersionStringOffset, 0, kVersionStringLength);
Version::GetString(
Vector<char>(data + kVersionStringOffset, kVersionStringLength));
memset(data + SnapshotImpl::kVersionStringOffset, 0,
SnapshotImpl::kVersionStringLength);
Version::GetString(Vector<char>(data + SnapshotImpl::kVersionStringOffset,
SnapshotImpl::kVersionStringLength));
// Startup snapshot (isolate-specific data).
uint32_t payload_offset = startup_snapshot_offset;
......@@ -201,7 +276,8 @@ v8::StartupData Snapshot::CreateSnapshotBlob(
payload_offset += payload_length;
// Read-only.
SetHeaderValue(data, kReadOnlyOffsetOffset, payload_offset);
SnapshotImpl::SetHeaderValue(data, SnapshotImpl::kReadOnlyOffsetOffset,
payload_offset);
payload_length = read_only_snapshot->RawData().length();
CopyBytes(
data + payload_offset,
......@@ -214,7 +290,8 @@ v8::StartupData Snapshot::CreateSnapshotBlob(
// Partial snapshots (context-specific data).
for (uint32_t i = 0; i < num_contexts; i++) {
SetHeaderValue(data, ContextSnapshotOffsetOffset(i), payload_offset);
SnapshotImpl::SetHeaderValue(
data, SnapshotImpl::ContextSnapshotOffsetOffset(i), payload_offset);
SnapshotData* context_snapshot = (*context_snapshots)[i];
payload_length = context_snapshot->RawData().length();
CopyBytes(
......@@ -233,12 +310,14 @@ v8::StartupData Snapshot::CreateSnapshotBlob(
DCHECK_EQ(total_length, payload_offset);
v8::StartupData result = {data, static_cast<int>(total_length)};
SetHeaderValue(data, kChecksumOffset, Checksum(ChecksummedContent(&result)));
SnapshotImpl::SetHeaderValue(
data, SnapshotImpl::kChecksumOffset,
Checksum(SnapshotImpl::ChecksummedContent(&result)));
return result;
}
uint32_t Snapshot::ExtractNumContexts(const v8::StartupData* data) {
uint32_t SnapshotImpl::ExtractNumContexts(const v8::StartupData* data) {
CHECK_LT(kNumberOfContextsOffset, data->raw_size);
uint32_t num_contexts = GetHeaderValue(data, kNumberOfContextsOffset);
return num_contexts;
......@@ -247,8 +326,9 @@ uint32_t Snapshot::ExtractNumContexts(const v8::StartupData* data) {
bool Snapshot::VerifyChecksum(const v8::StartupData* data) {
base::ElapsedTimer timer;
if (FLAG_profile_deserialization) timer.Start();
uint32_t expected = GetHeaderValue(data, kChecksumOffset);
uint32_t result = Checksum(ChecksummedContent(data));
uint32_t expected =
SnapshotImpl::GetHeaderValue(data, SnapshotImpl::kChecksumOffset);
uint32_t result = Checksum(SnapshotImpl::ChecksummedContent(data));
if (FLAG_profile_deserialization) {
double ms = timer.Elapsed().InMillisecondsF();
PrintF("[Verifying snapshot checksum took %0.3f ms]\n", ms);
......@@ -256,8 +336,8 @@ bool Snapshot::VerifyChecksum(const v8::StartupData* data) {
return result == expected;
}
uint32_t Snapshot::ExtractContextOffset(const v8::StartupData* data,
uint32_t index) {
uint32_t SnapshotImpl::ExtractContextOffset(const v8::StartupData* data,
uint32_t index) {
// Extract the offset of the context at a given index from the StartupData,
// and check that it is within bounds.
uint32_t context_offset =
......@@ -267,8 +347,10 @@ uint32_t Snapshot::ExtractContextOffset(const v8::StartupData* data,
}
bool Snapshot::ExtractRehashability(const v8::StartupData* data) {
CHECK_LT(kRehashabilityOffset, static_cast<uint32_t>(data->raw_size));
uint32_t rehashability = GetHeaderValue(data, kRehashabilityOffset);
CHECK_LT(SnapshotImpl::kRehashabilityOffset,
static_cast<uint32_t>(data->raw_size));
uint32_t rehashability =
SnapshotImpl::GetHeaderValue(data, SnapshotImpl::kRehashabilityOffset);
CHECK_IMPLIES(rehashability != 0, rehashability == 1);
return rehashability != 0;
}
......@@ -285,23 +367,25 @@ Vector<const byte> ExtractData(const v8::StartupData* snapshot,
}
} // namespace
Vector<const byte> Snapshot::ExtractStartupData(const v8::StartupData* data) {
DCHECK(SnapshotIsValid(data));
Vector<const byte> SnapshotImpl::ExtractStartupData(
const v8::StartupData* data) {
DCHECK(Snapshot::SnapshotIsValid(data));
uint32_t num_contexts = ExtractNumContexts(data);
return ExtractData(data, StartupSnapshotOffset(num_contexts),
GetHeaderValue(data, kReadOnlyOffsetOffset));
}
Vector<const byte> Snapshot::ExtractReadOnlyData(const v8::StartupData* data) {
DCHECK(SnapshotIsValid(data));
Vector<const byte> SnapshotImpl::ExtractReadOnlyData(
const v8::StartupData* data) {
DCHECK(Snapshot::SnapshotIsValid(data));
return ExtractData(data, GetHeaderValue(data, kReadOnlyOffsetOffset),
GetHeaderValue(data, ContextSnapshotOffsetOffset(0)));
}
Vector<const byte> Snapshot::ExtractContextData(const v8::StartupData* data,
uint32_t index) {
Vector<const byte> SnapshotImpl::ExtractContextData(const v8::StartupData* data,
uint32_t index) {
uint32_t num_contexts = ExtractNumContexts(data);
CHECK_LT(index, num_contexts);
......@@ -320,7 +404,7 @@ Vector<const byte> Snapshot::ExtractContextData(const v8::StartupData* data,
return Vector<const byte>(context_data, context_length);
}
void Snapshot::CheckVersion(const v8::StartupData* data) {
void SnapshotImpl::CheckVersion(const v8::StartupData* data) {
char version[kVersionStringLength];
memset(version, 0, kVersionStringLength);
CHECK_LT(kVersionStringOffset + kVersionStringLength,
......
src/snapshot/snapshot.h
View file @ cdb845b0
// Copyright 2006-2008 the V8 project authors. All rights reserved.
// Copyright 2020 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_SNAPSHOT_H_
#define V8_SNAPSHOT_SNAPSHOT_H_
#include "include/v8.h"
#include "src/base/memory.h"
#include "src/utils/vector.h"
#include "include/v8.h" // For StartupData.
#include "src/common/globals.h"
namespace v8 {
namespace internal {
......@@ -19,7 +17,15 @@ class JSGlobalProxy;
class Snapshot : public AllStatic {
public:
// ---------------- Deserialization ----------------
// ---------------- Serialization -------------------------------------------
static v8::StartupData CreateSnapshotBlob(
const SnapshotData* startup_snapshot_in,
const SnapshotData* read_only_snapshot_in,
const std::vector<SnapshotData*>& context_snapshots_in,
bool can_be_rehashed);
// ---------------- Deserialization -----------------------------------------
// Initialize the Isolate from the internal snapshot. Returns false if no
// snapshot could be found.
......@@ -31,95 +37,19 @@ class Snapshot : public AllStatic {
size_t context_index,
v8::DeserializeEmbedderFieldsCallback embedder_fields_deserializer);
// ---------------- Helper methods ----------------
// ---------------- Helper methods ------------------------------------------
static bool HasContextSnapshot(Isolate* isolate, size_t index);
static bool EmbedsScript(Isolate* isolate);
V8_EXPORT_PRIVATE static bool VerifyChecksum(const v8::StartupData* data);
static bool ExtractRehashability(const v8::StartupData* data);
// To be implemented by the snapshot source.
static const v8::StartupData* DefaultSnapshotBlob();
V8_EXPORT_PRIVATE static bool VerifyChecksum(const v8::StartupData* data);
// ---------------- Serialization ----------------
static v8::StartupData CreateSnapshotBlob(
const SnapshotData* startup_snapshot_in,
const SnapshotData* read_only_snapshot_in,
const std::vector<SnapshotData*>& context_snapshots_in,
bool can_be_rehashed);
#ifdef DEBUG
static bool SnapshotIsValid(const v8::StartupData* snapshot_blob);
#endif // DEBUG
static bool ExtractRehashability(const v8::StartupData* data);
private:
static uint32_t ExtractNumContexts(const v8::StartupData* data);
static uint32_t ExtractContextOffset(const v8::StartupData* data,
uint32_t index);
static Vector<const byte> ExtractStartupData(const v8::StartupData* data);
static Vector<const byte> ExtractReadOnlyData(const v8::StartupData* data);
static Vector<const byte> ExtractContextData(const v8::StartupData* data,
uint32_t index);
static uint32_t GetHeaderValue(const v8::StartupData* data, uint32_t offset) {
return base::ReadLittleEndianValue<uint32_t>(
reinterpret_cast<Address>(data->data) + offset);
}
static void SetHeaderValue(char* data, uint32_t offset, uint32_t value) {
base::WriteLittleEndianValue(reinterpret_cast<Address>(data) + offset,
value);
}
static void CheckVersion(const v8::StartupData* data);
// Snapshot blob layout:
// [0] number of contexts N
// [1] rehashability
// [2] checksum
// [3] (128 bytes) version string
// [4] offset to readonly
// [5] offset to context 0
// [6] offset to context 1
// ...
// ... offset to context N - 1
// ... startup snapshot data
// ... read-only snapshot data
// ... context 0 snapshot data
// ... context 1 snapshot data
static const uint32_t kNumberOfContextsOffset = 0;
// TODO(yangguo): generalize rehashing, and remove this flag.
static const uint32_t kRehashabilityOffset =
kNumberOfContextsOffset + kUInt32Size;
static const uint32_t kChecksumOffset = kRehashabilityOffset + kUInt32Size;
static const uint32_t kVersionStringOffset = kChecksumOffset + kUInt32Size;
static const uint32_t kVersionStringLength = 64;
static const uint32_t kReadOnlyOffsetOffset =
kVersionStringOffset + kVersionStringLength;
static const uint32_t kFirstContextOffsetOffset =
kReadOnlyOffsetOffset + kUInt32Size;
static Vector<const byte> ChecksummedContent(const v8::StartupData* data) {
STATIC_ASSERT(kVersionStringOffset == kChecksumOffset + kUInt32Size);
const uint32_t kChecksumStart = kVersionStringOffset;
return Vector<const byte>(
reinterpret_cast<const byte*>(data->data + kChecksumStart),
data->raw_size - kChecksumStart);
}
static uint32_t StartupSnapshotOffset(int num_contexts) {
return POINTER_SIZE_ALIGN(kFirstContextOffsetOffset +
num_contexts * kInt32Size);
}
static uint32_t ContextSnapshotOffsetOffset(int index) {
return kFirstContextOffsetOffset + index * kInt32Size;
}
DISALLOW_IMPLICIT_CONSTRUCTORS(Snapshot);
};
// Convenience wrapper around snapshot data blob creation used e.g. by tests and
......
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