V8 支持堆快照就是为了这个目的。例如,Atom 编辑器使用它来缩短启动时间。与其说是预编译,不如说是预编译你的全局环境和实例化你的函数(可能还没有编译,只是转换为Ignition的字节码,这就足够了)。如果您使用的是 Electron,mksnapshot
npm 包可能很有用。(如果没有,看看它是如何工作的可能仍然有用。)
我没有做过任何 V8 黑客攻击,但他们从上面的博客文章中链接的示例如下:
TEST(PerIsolateSnapshotBlobs) {
DisableTurbofan();
const char* source1 = "function f() { return 42; }";
const char* source2 =
"function f() { return g() * 2; }"
"function g() { return 43; }"
"/./.test('a')";
v8::StartupData data1 = v8::V8::CreateSnapshotDataBlob(source1);
v8::StartupData data2 = v8::V8::CreateSnapshotDataBlob(source2);
v8::Isolate::CreateParams params1;
params1.snapshot_blob = &data1;
params1.array_buffer_allocator = CcTest::array_buffer_allocator();
v8::Isolate* isolate1 = v8::Isolate::New(params1);
{
v8::Isolate::Scope i_scope(isolate1);
v8::HandleScope h_scope(isolate1);
v8::Local<v8::Context> context = v8::Context::New(isolate1);
delete[] data1.data; // We can dispose of the snapshot blob now.
v8::Context::Scope c_scope(context);
CHECK_EQ(42, CompileRun("f()")->ToInt32(isolate1)->Int32Value());
CHECK(CompileRun("this.g")->IsUndefined());
}
isolate1->Dispose();
v8::Isolate::CreateParams params2;
params2.snapshot_blob = &data2;
params2.array_buffer_allocator = CcTest::array_buffer_allocator();
v8::Isolate* isolate2 = v8::Isolate::New(params2);
{
v8::Isolate::Scope i_scope(isolate2);
v8::HandleScope h_scope(isolate2);
v8::Local<v8::Context> context = v8::Context::New(isolate2);
delete[] data2.data; // We can dispose of the snapshot blob now.
v8::Context::Scope c_scope(context);
CHECK_EQ(86, CompileRun("f()")->ToInt32(isolate2)->Int32Value());
CHECK_EQ(43, CompileRun("g()")->ToInt32(isolate2)->Int32Value());
}
isolate2->Dispose();
}
那篇博文(以及相关的例子?)是从 2015 年开始的,所以从那以后事情可能已经发生了变化。