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// Copyright 2006-2008 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.
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <iomanip>
#include "include/libplatform/libplatform.h"
#include "src/base/platform/platform.h"
#include "src/codegen/assembler-arch.h"
#include "src/codegen/source-position-table.h"
#include "src/flags/flags.h"
#include "src/sanitizer/msan.h"
#include "src/snapshot/embedded/embedded-file-writer.h"
#include "src/snapshot/partial-serializer.h"
#include "src/snapshot/snapshot.h"
#include "src/snapshot/startup-serializer.h"
namespace {
class SnapshotFileWriter {
public:
void SetSnapshotFile(const char* snapshot_cpp_file) {
snapshot_cpp_path_ = snapshot_cpp_file;
}
void SetStartupBlobFile(const char* snapshot_blob_file) {
snapshot_blob_path_ = snapshot_blob_file;
}
void WriteSnapshot(v8::StartupData blob) const {
// TODO(crbug/633159): if we crash before the files have been fully created,
// we end up with a corrupted snapshot file. The build step would succeed,
// but the build target is unusable. Ideally we would write out temporary
// files and only move them to the final destination as last step.
i::Vector<const i::byte> blob_vector(
reinterpret_cast<const i::byte*>(blob.data), blob.raw_size);
MaybeWriteSnapshotFile(blob_vector);
MaybeWriteStartupBlob(blob_vector);
}
private:
void MaybeWriteStartupBlob(const i::Vector<const i::byte>& blob) const {
if (!snapshot_blob_path_) return;
FILE* fp = GetFileDescriptorOrDie(snapshot_blob_path_);
size_t written = fwrite(blob.begin(), 1, blob.length(), fp);
fclose(fp);
if (written != static_cast<size_t>(blob.length())) {
i::PrintF("Writing snapshot file failed.. Aborting.\n");
remove(snapshot_blob_path_);
exit(1);
}
}
void MaybeWriteSnapshotFile(const i::Vector<const i::byte>& blob) const {
if (!snapshot_cpp_path_) return;
FILE* fp = GetFileDescriptorOrDie(snapshot_cpp_path_);
WriteSnapshotFilePrefix(fp);
WriteSnapshotFileData(fp, blob);
WriteSnapshotFileSuffix(fp);
fclose(fp);
}
static void WriteSnapshotFilePrefix(FILE* fp) {
fprintf(fp, "// Autogenerated snapshot file. Do not edit.\n\n");
fprintf(fp, "#include \"src/init/v8.h\"\n");
fprintf(fp, "#include \"src/base/platform/platform.h\"\n\n");
fprintf(fp, "#include \"src/snapshot/snapshot.h\"\n\n");
fprintf(fp, "namespace v8 {\n");
fprintf(fp, "namespace internal {\n\n");
}
static void WriteSnapshotFileSuffix(FILE* fp) {
fprintf(fp, "const v8::StartupData* Snapshot::DefaultSnapshotBlob() {\n");
fprintf(fp, " return &blob;\n");
fprintf(fp, "}\n\n");
fprintf(fp, "} // namespace internal\n");
fprintf(fp, "} // namespace v8\n");
}
static void WriteSnapshotFileData(FILE* fp,
const i::Vector<const i::byte>& blob) {
fprintf(fp,
"alignas(kPointerAlignment) static const byte blob_data[] = {\n");
WriteBinaryContentsAsCArray(fp, blob);
fprintf(fp, "};\n");
fprintf(fp, "static const int blob_size = %d;\n", blob.length());
fprintf(fp, "static const v8::StartupData blob =\n");
fprintf(fp, "{ (const char*) blob_data, blob_size };\n");
}
static void WriteBinaryContentsAsCArray(
FILE* fp, const i::Vector<const i::byte>& blob) {
for (int i = 0; i < blob.length(); i++) {
if ((i & 0x1F) == 0x1F) fprintf(fp, "\n");
if (i > 0) fprintf(fp, ",");
fprintf(fp, "%u", static_cast<unsigned char>(blob.at(i)));
}
fprintf(fp, "\n");
}
static FILE* GetFileDescriptorOrDie(const char* filename) {
FILE* fp = v8::base::OS::FOpen(filename, "wb");
if (fp == nullptr) {
i::PrintF("Unable to open file \"%s\" for writing.\n", filename);
exit(1);
}
return fp;
}
const char* snapshot_cpp_path_ = nullptr;
const char* snapshot_blob_path_ = nullptr;
};
char* GetExtraCode(char* filename, const char* description) {
if (filename == nullptr || strlen(filename) == 0) return nullptr;
::printf("Loading script for %s: %s\n", description, filename);
FILE* file = v8::base::OS::FOpen(filename, "rb");
if (file == nullptr) {
fprintf(stderr, "Failed to open '%s': errno %d\n", filename, errno);
exit(1);
}
fseek(file, 0, SEEK_END);
size_t size = ftell(file);
rewind(file);
char* chars = new char[size + 1];
chars[size] = '\0';
for (size_t i = 0; i < size;) {
size_t read = fread(&chars[i], 1, size - i, file);
if (ferror(file)) {
fprintf(stderr, "Failed to read '%s': errno %d\n", filename, errno);
exit(1);
}
i += read;
}
fclose(file);
return chars;
}
v8::StartupData CreateSnapshotDataBlob(v8::Isolate* isolate,
const char* embedded_source) {
v8::base::ElapsedTimer timer;
timer.Start();
v8::StartupData result = i::CreateSnapshotDataBlobInternal(
v8::SnapshotCreator::FunctionCodeHandling::kClear, embedded_source,
isolate);
if (i::FLAG_profile_deserialization) {
i::PrintF("Creating snapshot took %0.3f ms\n",
timer.Elapsed().InMillisecondsF());
}
timer.Stop();
return result;
}
v8::StartupData WarmUpSnapshotDataBlob(v8::StartupData cold_snapshot_blob,
const char* warmup_source) {
v8::base::ElapsedTimer timer;
timer.Start();
v8::StartupData result =
i::WarmUpSnapshotDataBlobInternal(cold_snapshot_blob, warmup_source);
if (i::FLAG_profile_deserialization) {
i::PrintF("Warming up snapshot took %0.3f ms\n",
timer.Elapsed().InMillisecondsF());
}
timer.Stop();
return result;
}
void WriteEmbeddedFile(i::EmbeddedFileWriter* writer) {
i::EmbeddedData embedded_blob = i::EmbeddedData::FromBlob();
writer->WriteEmbedded(&embedded_blob);
}
using CounterMap = std::map<std::string, int>;
CounterMap* counter_map_ = nullptr;
void MaybeSetCounterFunction(v8::Isolate* isolate) {
// If --native-code-counters is on then we enable all counters to make
// sure we generate code to increment them from the snapshot.
//
// Note: For the sake of the mksnapshot, the counter function must only
// return distinct addresses for each counter s.t. the serializer can properly
// distinguish between them. In theory it should be okay to just return an
// incremented int value each time this function is called, but we play it
// safe and return a real distinct memory location tied to every counter name.
if (i::FLAG_native_code_counters) {
counter_map_ = new CounterMap();
isolate->SetCounterFunction([](const char* name) -> int* {
auto map_entry = counter_map_->find(name);
if (map_entry == counter_map_->end()) {
counter_map_->emplace(name, 0);
}
return &counter_map_->at(name);
});
}
}
} // namespace
int main(int argc, char** argv) {
v8::base::EnsureConsoleOutput();
// Make mksnapshot runs predictable to create reproducible snapshots.
i::FLAG_predictable = true;
// Print the usage if an error occurs when parsing the command line
// flags or if the help flag is set.
int result = i::FlagList::SetFlagsFromCommandLine(&argc, argv, true);
if (result > 0 || (argc > 3) || i::FLAG_help) {
::printf("Usage: %s --startup_src=... --startup_blob=... [extras]\n",
argv[0]);
i::FlagList::PrintHelp();
return !i::FLAG_help;
}
i::CpuFeatures::Probe(true);
v8::V8::InitializeICUDefaultLocation(argv[0]);
std::unique_ptr<v8::Platform> platform = v8::platform::NewDefaultPlatform();
v8::V8::InitializePlatform(platform.get());
v8::V8::Initialize();
{
SnapshotFileWriter snapshot_writer;
snapshot_writer.SetSnapshotFile(i::FLAG_startup_src);
snapshot_writer.SetStartupBlobFile(i::FLAG_startup_blob);
i::EmbeddedFileWriter embedded_writer;
embedded_writer.SetEmbeddedFile(i::FLAG_embedded_src);
embedded_writer.SetEmbeddedVariant(i::FLAG_embedded_variant);
embedded_writer.SetTargetArch(i::FLAG_target_arch);
embedded_writer.SetTargetOs(i::FLAG_target_os);
std::unique_ptr<char> embed_script(
GetExtraCode(argc >= 2 ? argv[1] : nullptr, "embedding"));
std::unique_ptr<char> warmup_script(
GetExtraCode(argc >= 3 ? argv[2] : nullptr, "warm up"));
i::DisableEmbeddedBlobRefcounting();
v8::StartupData blob;
{
v8::Isolate* isolate = v8::Isolate::Allocate();
MaybeSetCounterFunction(isolate);
// Set code range such that relative jumps for builtins to
// builtin calls in the snapshot are possible.
i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
size_t code_range_size_mb =
i::kMaximalCodeRangeSize == 0
? i::kMaxPCRelativeCodeRangeInMB
: std::min(i::kMaximalCodeRangeSize / i::MB,
i::kMaxPCRelativeCodeRangeInMB);
v8::ResourceConstraints constraints;
constraints.set_code_range_size_in_bytes(code_range_size_mb * i::MB);
i_isolate->heap()->ConfigureHeap(constraints);
// The isolate contains data from builtin compilation that needs
// to be written out if builtins are embedded.
i_isolate->RegisterEmbeddedFileWriter(&embedded_writer);
blob = CreateSnapshotDataBlob(isolate, embed_script.get());
// At this point, the Isolate has been torn down but the embedded blob
// is still alive (we called DisableEmbeddedBlobRefcounting above).
// That's fine as far as the embedded file writer is concerned.
WriteEmbeddedFile(&embedded_writer);
}
if (warmup_script) {
v8::StartupData cold = blob;
blob = WarmUpSnapshotDataBlob(cold, warmup_script.get());
delete[] cold.data;
}
delete counter_map_;
CHECK(blob.data);
snapshot_writer.WriteSnapshot(blob);
delete[] blob.data;
}
i::FreeCurrentEmbeddedBlob();
v8::V8::Dispose();
v8::V8::ShutdownPlatform();
return 0;
}
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