gin: Hide V8 context snapshot behind a build flag
We had V8 context snapshot in C++ code regardless V8 settings,
but it introduced some complex errors.
This CL disables usages of V8 context snapshot if a GN flag
"v8_use_external_startup_data" is not true, because V8 context
snapshot depends on what is built with the flag.
Bug: 764576
Change-Id: If9b1cc497a6f6122f213b83ed2f9746d9af8bb62
Reviewed-on: https://chromium-review.googlesource.com/788631
Reviewed-by: Kinuko Yasuda <[email protected]>
Reviewed-by: Ross McIlroy <[email protected]>
Commit-Queue: Hitoshi Yoshida <[email protected]>
Cr-Commit-Position: refs/heads/master@{#519208}diff --git a/gin/v8_initializer.cc b/gin/v8_initializer.cc
index e4ff07f..03353be 100644
--- a/gin/v8_initializer.cc
+++ b/gin/v8_initializer.cc
@@ -43,7 +43,23 @@
base::MemoryMappedFile* g_mapped_snapshot = nullptr;
base::MemoryMappedFile* g_mapped_v8_context_snapshot = nullptr;
-const char kV8ContextSnapshotFileName[] = "v8_context_snapshot.bin";
+bool GenerateEntropy(unsigned char* buffer, size_t amount) {
+ base::RandBytes(buffer, amount);
+ return true;
+}
+
+void GetMappedFileData(base::MemoryMappedFile* mapped_file,
+ v8::StartupData* data) {
+ if (mapped_file) {
+ data->data = reinterpret_cast<const char*>(mapped_file->data());
+ data->raw_size = static_cast<int>(mapped_file->length());
+ } else {
+ data->data = nullptr;
+ data->raw_size = 0;
+ }
+}
+
+#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
// File handles intentionally never closed. Not using File here because its
// Windows implementation guards against two instances owning the same
@@ -54,9 +70,8 @@
base::LazyInstance<OpenedFileMap>::Leaky g_opened_files =
LAZY_INSTANCE_INITIALIZER;
-#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
-
const char kNativesFileName[] = "natives_blob.bin";
+const char kV8ContextSnapshotFileName[] = "v8_context_snapshot.bin";
#if defined(OS_ANDROID)
const char kSnapshotFileName64[] = "snapshot_blob_64.bin";
@@ -72,8 +87,6 @@
const char kSnapshotFileName[] = "snapshot_blob.bin";
#endif // defined(OS_ANDROID)
-#endif // defined(V8_USE_EXTERNAL_STATUP_DATA)
-
void GetV8FilePath(const char* file_name, base::FilePath* path_out) {
#if !defined(OS_MACOSX)
base::FilePath data_path;
@@ -188,11 +201,6 @@
return opened_file;
}
-bool GenerateEntropy(unsigned char* buffer, size_t amount) {
- base::RandBytes(buffer, amount);
- return true;
-}
-
enum LoadV8FileResult {
V8_LOAD_SUCCESS = 0,
V8_LOAD_FAILED_OPEN,
@@ -210,114 +218,10 @@
return V8_LOAD_SUCCESS;
}
-void GetMappedFileData(base::MemoryMappedFile* mapped_file,
- v8::StartupData* data) {
- if (mapped_file) {
- data->data = reinterpret_cast<const char*>(mapped_file->data());
- data->raw_size = static_cast<int>(mapped_file->length());
- } else {
- data->data = nullptr;
- data->raw_size = 0;
- }
-}
+#endif // defined(V8_USE_EXTERNAL_STATUP_DATA)
} // namespace
-#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
-
-// static
-void V8Initializer::LoadV8Snapshot() {
- if (g_mapped_snapshot)
- return;
-
- LoadV8FileResult result = MapOpenedFile(GetOpenedFile(kSnapshotFileName),
- &g_mapped_snapshot);
- // V8 can't start up without the source of the natives, but it can
- // start up (slower) without the snapshot.
- UMA_HISTOGRAM_ENUMERATION("V8.Initializer.LoadV8Snapshot.Result", result,
- V8_LOAD_MAX_VALUE);
-}
-
-void V8Initializer::LoadV8Natives() {
- if (g_mapped_natives)
- return;
-
- LoadV8FileResult result = MapOpenedFile(GetOpenedFile(kNativesFileName),
- &g_mapped_natives);
- if (result != V8_LOAD_SUCCESS) {
- LOG(FATAL) << "Couldn't mmap v8 natives data file, status code is "
- << static_cast<int>(result);
- }
-}
-
-// static
-void V8Initializer::LoadV8SnapshotFromFD(base::PlatformFile snapshot_pf,
- int64_t snapshot_offset,
- int64_t snapshot_size) {
- if (g_mapped_snapshot)
- return;
-
- if (snapshot_pf == base::kInvalidPlatformFile)
- return;
-
- base::MemoryMappedFile::Region snapshot_region =
- base::MemoryMappedFile::Region::kWholeFile;
- if (snapshot_size != 0 || snapshot_offset != 0) {
- snapshot_region.offset = snapshot_offset;
- snapshot_region.size = snapshot_size;
- }
-
- LoadV8FileResult result = V8_LOAD_SUCCESS;
- if (!MapV8File(snapshot_pf, snapshot_region, &g_mapped_snapshot))
- result = V8_LOAD_FAILED_MAP;
- if (result == V8_LOAD_SUCCESS) {
- g_opened_files.Get()[kSnapshotFileName] =
- std::make_pair(snapshot_pf, snapshot_region);
- }
- UMA_HISTOGRAM_ENUMERATION("V8.Initializer.LoadV8Snapshot.Result", result,
- V8_LOAD_MAX_VALUE);
-}
-
-// static
-void V8Initializer::LoadV8NativesFromFD(base::PlatformFile natives_pf,
- int64_t natives_offset,
- int64_t natives_size) {
- if (g_mapped_natives)
- return;
-
- CHECK_NE(natives_pf, base::kInvalidPlatformFile);
-
- base::MemoryMappedFile::Region natives_region =
- base::MemoryMappedFile::Region::kWholeFile;
- if (natives_size != 0 || natives_offset != 0) {
- natives_region.offset = natives_offset;
- natives_region.size = natives_size;
- }
-
- if (!MapV8File(natives_pf, natives_region, &g_mapped_natives)) {
- LOG(FATAL) << "Couldn't mmap v8 natives data file";
- }
- g_opened_files.Get()[kNativesFileName] =
- std::make_pair(natives_pf, natives_region);
-}
-
-#if defined(OS_ANDROID)
-// static
-base::FilePath V8Initializer::GetNativesFilePath() {
- base::FilePath path;
- GetV8FilePath(kNativesFileName, &path);
- return path;
-}
-
-// static
-base::FilePath V8Initializer::GetSnapshotFilePath(bool abi_32_bit) {
- base::FilePath path;
- GetV8FilePath(abi_32_bit ? kSnapshotFileName32 : kSnapshotFileName64, &path);
- return path;
-}
-#endif // defined(OS_ANDROID)
-#endif // defined(V8_USE_EXTERNAL_STARTUP_DATA)
-
// static
void V8Initializer::Initialize(IsolateHolder::ScriptMode mode,
IsolateHolder::V8ExtrasMode v8_extras_mode) {
@@ -378,6 +282,38 @@
}
// static
+void V8Initializer::GetV8ContextSnapshotData(v8::StartupData* snapshot) {
+ GetMappedFileData(g_mapped_v8_context_snapshot, snapshot);
+}
+
+#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+
+// static
+void V8Initializer::LoadV8Snapshot() {
+ if (g_mapped_snapshot)
+ return;
+
+ LoadV8FileResult result = MapOpenedFile(GetOpenedFile(kSnapshotFileName),
+ &g_mapped_snapshot);
+ // V8 can't start up without the source of the natives, but it can
+ // start up (slower) without the snapshot.
+ UMA_HISTOGRAM_ENUMERATION("V8.Initializer.LoadV8Snapshot.Result", result,
+ V8_LOAD_MAX_VALUE);
+}
+
+void V8Initializer::LoadV8Natives() {
+ if (g_mapped_natives)
+ return;
+
+ LoadV8FileResult result = MapOpenedFile(GetOpenedFile(kNativesFileName),
+ &g_mapped_natives);
+ if (result != V8_LOAD_SUCCESS) {
+ LOG(FATAL) << "Couldn't mmap v8 natives data file, status code is "
+ << static_cast<int>(result);
+ }
+}
+
+// static
void V8Initializer::LoadV8ContextSnapshot() {
if (g_mapped_v8_context_snapshot)
return;
@@ -389,6 +325,57 @@
}
// static
+void V8Initializer::LoadV8SnapshotFromFD(base::PlatformFile snapshot_pf,
+ int64_t snapshot_offset,
+ int64_t snapshot_size) {
+ if (g_mapped_snapshot)
+ return;
+
+ if (snapshot_pf == base::kInvalidPlatformFile)
+ return;
+
+ base::MemoryMappedFile::Region snapshot_region =
+ base::MemoryMappedFile::Region::kWholeFile;
+ if (snapshot_size != 0 || snapshot_offset != 0) {
+ snapshot_region.offset = snapshot_offset;
+ snapshot_region.size = snapshot_size;
+ }
+
+ LoadV8FileResult result = V8_LOAD_SUCCESS;
+ if (!MapV8File(snapshot_pf, snapshot_region, &g_mapped_snapshot))
+ result = V8_LOAD_FAILED_MAP;
+ if (result == V8_LOAD_SUCCESS) {
+ g_opened_files.Get()[kSnapshotFileName] =
+ std::make_pair(snapshot_pf, snapshot_region);
+ }
+ UMA_HISTOGRAM_ENUMERATION("V8.Initializer.LoadV8Snapshot.Result", result,
+ V8_LOAD_MAX_VALUE);
+}
+
+// static
+void V8Initializer::LoadV8NativesFromFD(base::PlatformFile natives_pf,
+ int64_t natives_offset,
+ int64_t natives_size) {
+ if (g_mapped_natives)
+ return;
+
+ CHECK_NE(natives_pf, base::kInvalidPlatformFile);
+
+ base::MemoryMappedFile::Region natives_region =
+ base::MemoryMappedFile::Region::kWholeFile;
+ if (natives_size != 0 || natives_offset != 0) {
+ natives_region.offset = natives_offset;
+ natives_region.size = natives_size;
+ }
+
+ if (!MapV8File(natives_pf, natives_region, &g_mapped_natives)) {
+ LOG(FATAL) << "Couldn't mmap v8 natives data file";
+ }
+ g_opened_files.Get()[kNativesFileName] =
+ std::make_pair(natives_pf, natives_region);
+}
+
+// static
void V8Initializer::LoadV8ContextSnapshotFromFD(base::PlatformFile snapshot_pf,
int64_t snapshot_offset,
int64_t snapshot_size) {
@@ -409,9 +396,21 @@
}
}
+#if defined(OS_ANDROID)
// static
-void V8Initializer::GetV8ContextSnapshotData(v8::StartupData* snapshot) {
- GetMappedFileData(g_mapped_v8_context_snapshot, snapshot);
+base::FilePath V8Initializer::GetNativesFilePath() {
+ base::FilePath path;
+ GetV8FilePath(kNativesFileName, &path);
+ return path;
}
+// static
+base::FilePath V8Initializer::GetSnapshotFilePath(bool abi_32_bit) {
+ base::FilePath path;
+ GetV8FilePath(abi_32_bit ? kSnapshotFileName32 : kSnapshotFileName64, &path);
+ return path;
+}
+#endif // defined(OS_ANDROID)
+#endif // defined(V8_USE_EXTERNAL_STARTUP_DATA)
+
} // namespace gin
diff --git a/gin/v8_initializer.h b/gin/v8_initializer.h
index 065fecb..0c0da3c7 100644
--- a/gin/v8_initializer.h
+++ b/gin/v8_initializer.h
@@ -33,8 +33,20 @@
const char** snapshot_data_out,
int* snapshot_size_out);
+ // Get address and size information for currently loaded V8 context snapshot.
+ // If no snapshot is loaded, the return values are nullptr and 0.
+ static void GetV8ContextSnapshotData(v8::StartupData* snapshot);
+
#if defined(V8_USE_EXTERNAL_STARTUP_DATA)
+ // Load V8 snapshot from default resources, if they are available.
+ static void LoadV8Snapshot();
+ // Load V8 natives source from default resources. Contains asserts
+ // so that it will not return if natives cannot be loaded.
+ static void LoadV8Natives();
+ // Load V8 context snapshot from default resources, if they are available.
+ static void LoadV8ContextSnapshot();
+
// Load V8 snapshot from user provided platform file descriptors.
// The offset and size arguments, if non-zero, specify the portions
// of the files to be loaded. Since the VM can boot with or without
@@ -48,13 +60,11 @@
static void LoadV8NativesFromFD(base::PlatformFile natives_fd,
int64_t natives_offset,
int64_t natives_size);
-
- // Load V8 snapshot from default resources, if they are available.
- static void LoadV8Snapshot();
-
- // Load V8 natives source from default resources. Contains asserts
- // so that it will not return if natives cannot be loaded.
- static void LoadV8Natives();
+ // Load V8 context snapshot from user provided platform file descriptors.
+ // Other details are same with LoadV8SnapshotFromFD.
+ static void LoadV8ContextSnapshotFromFD(base::PlatformFile snapshot_fd,
+ int64_t snapshot_offset,
+ int64_t snapshot_size);
#if defined(OS_ANDROID)
static base::FilePath GetNativesFilePath();
@@ -63,18 +73,6 @@
#endif // V8_USE_EXTERNAL_STARTUP_DATA
- // Load V8 context snapshot from user provided platform file descriptors.
- // Other details are same with LoadV8SnapshotFromFD.
- static void LoadV8ContextSnapshotFromFD(base::PlatformFile snapshot_fd,
- int64_t snapshot_offset,
- int64_t snapshot_size);
-
- // Load V8 context snapshot from default resources, if they are available.
- static void LoadV8ContextSnapshot();
-
- // Get address and size information for currently loaded V8 context snapshot.
- // If no snapshot is loaded, the return values are nullptr and 0.
- static void GetV8ContextSnapshotData(v8::StartupData* snapshot);
};
} // namespace gin
