VM: [Kernel] Fix bootstraping when Kernel isolate is used.

runtime/vm/kernel_isolate.cc

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/kernel_isolate.h"
 
 #include "vm/compiler.h"
+#include "include/dart_native_api.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/isolate.h"
 #include "vm/lockers.h"
 #include "vm/message.h"
 #include "vm/message_handler.h"
 #include "vm/native_entry.h"
 #include "vm/native_arguments.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/port.h"
 #include "vm/service.h"
 #include "vm/symbols.h"
 #include "vm/thread_pool.h"
 #include "vm/timeline.h"
 
 namespace dart {
 
 #if !defined(DART_PRECOMPILED_RUNTIME)
 
 #define Z (T->zone())
 
 DEFINE_FLAG(bool, trace_kernel, false, "Trace Kernel service requests.");
 DEFINE_FLAG(bool,
             use_dart_frontend,
             false,
             "Parse scripts with Dart-to-Kernel parser");
 
-const char* KernelIsolate::kName = "kernel-service";
+const char* KernelIsolate::kName = DART_KERNEL_ISOLATE_NAME;
 Dart_IsolateCreateCallback KernelIsolate::create_callback_ = NULL;
 Monitor* KernelIsolate::monitor_ = new Monitor();
 Isolate* KernelIsolate::isolate_ = NULL;
 bool KernelIsolate::initializing_ = true;
 Dart_Port KernelIsolate::kernel_port_ = ILLEGAL_PORT;
 
 
 class RunKernelTask : public ThreadPool::Task {
  public:
   virtual void Run() {
@@ skipping 20 matching lines @@
       return;
     }
 
     Dart_IsolateFlags api_flags;
     Isolate::FlagsInitialize(&api_flags);
 
     isolate = reinterpret_cast<Isolate*>(create_callback(
         KernelIsolate::kName, NULL, NULL, NULL, &api_flags, NULL, &error));
     if (isolate == NULL) {
       if (FLAG_trace_kernel) {
-        OS::PrintErr("kernel-service: Isolate creation error: %s\n", error);
+        OS::PrintErr(DART_KERNEL_ISOLATE_NAME ": Isolate creation error: %s\n",
+                     error);
       }
       KernelIsolate::SetKernelIsolate(NULL);
       KernelIsolate::FinishedInitializing();
       return;
     }
 
     bool init_success = false;
     {
       ASSERT(Isolate::Current() == NULL);
       StartIsolateScope start_scope(isolate);
       init_success = RunMain(isolate);
     }
     KernelIsolate::FinishedInitializing();
 
     if (!init_success) {
       ShutdownIsolate(reinterpret_cast<uword>(isolate));
       return;
     }
 
     // isolate_ was set as side effect of create callback.
     ASSERT(KernelIsolate::IsKernelIsolate(isolate));
 
     isolate->message_handler()->Run(Dart::thread_pool(), NULL, ShutdownIsolate,
                                     reinterpret_cast<uword>(isolate));
   }
 
  protected:
   static void ShutdownIsolate(uword parameter) {
     if (FLAG_trace_kernel) {
-      OS::Print("kernel-service: ShutdownIsolate\n");
+      OS::Print(DART_KERNEL_ISOLATE_NAME ": ShutdownIsolate\n");
     }
     Isolate* I = reinterpret_cast<Isolate*>(parameter);
     ASSERT(KernelIsolate::IsKernelIsolate(I));
     KernelIsolate::SetKernelIsolate(NULL);
     KernelIsolate::SetLoadPort(ILLEGAL_PORT);
     I->WaitForOutstandingSpawns();
     {
       // Print the error if there is one.  This may execute dart code to
       // print the exception object, so we need to use a StartIsolateScope.
       ASSERT(Isolate::Current() == NULL);
       StartIsolateScope start_scope(I);
       Thread* T = Thread::Current();
       ASSERT(I == T->isolate());
       StackZone zone(T);
       HandleScope handle_scope(T);
       Error& error = Error::Handle(Z);
       error = T->sticky_error();
       if (!error.IsNull() && !error.IsUnwindError()) {
-        OS::PrintErr("kernel-service: Error: %s\n", error.ToErrorCString());
+        OS::PrintErr(DART_KERNEL_ISOLATE_NAME ": Error: %s\n",
+                     error.ToErrorCString());
       }
       error = I->sticky_error();
       if (!error.IsNull() && !error.IsUnwindError()) {
-        OS::PrintErr("kernel-service: Error: %s\n", error.ToErrorCString());
+        OS::PrintErr(DART_KERNEL_ISOLATE_NAME ": Error: %s\n",
+                     error.ToErrorCString());
       }
       Dart::RunShutdownCallback();
     }
     // Shut the isolate down.
     Dart::ShutdownIsolate(I);
     if (FLAG_trace_kernel) {
-      OS::Print("kernel-service: Shutdown.\n");
+      OS::Print(DART_KERNEL_ISOLATE_NAME ": Shutdown.\n");
     }
   }
 
   bool RunMain(Isolate* I) {
     Thread* T = Thread::Current();
     ASSERT(I == T->isolate());
     StackZone zone(T);
     HANDLESCOPE(T);
     // Invoke main which will return the port to which load requests are sent.
     const Library& root_library =
         Library::Handle(Z, I->object_store()->root_library());
     if (root_library.IsNull()) {
       if (FLAG_trace_kernel) {
-        OS::Print("kernel-service: Embedder did not install a script.");
+        OS::Print(DART_KERNEL_ISOLATE_NAME
+                  ": Embedder did not install a script.");
       }
       // Kernel isolate is not supported by embedder.
       return false;
     }
     ASSERT(!root_library.IsNull());
     const String& entry_name = String::Handle(Z, String::New("main"));
     ASSERT(!entry_name.IsNull());
     const Function& entry = Function::Handle(
         Z, root_library.LookupFunctionAllowPrivate(entry_name));
     if (entry.IsNull()) {
       // Kernel isolate is not supported by embedder.
       if (FLAG_trace_kernel) {
-        OS::Print("kernel-service: Embedder did not provide a main function.");
+        OS::Print(DART_KERNEL_ISOLATE_NAME
+                  ": Embedder did not provide a main function.");
       }
       return false;
     }
     ASSERT(!entry.IsNull());
     const Object& result = Object::Handle(
         Z, DartEntry::InvokeFunction(entry, Object::empty_array()));
     ASSERT(!result.IsNull());
     if (result.IsError()) {
       // Kernel isolate did not initialize properly.
       if (FLAG_trace_kernel) {
         const Error& error = Error::Cast(result);
-        OS::Print("kernel-service: Calling main resulted in an error: %s",
+        OS::Print(DART_KERNEL_ISOLATE_NAME
+                  ": Calling main resulted in an error: %s",
                   error.ToErrorCString());
       }
       return false;
     }
     ASSERT(result.IsReceivePort());
     const ReceivePort& rp = ReceivePort::Cast(result);
     KernelIsolate::SetLoadPort(rp.Id());
     return true;
   }
 };
 
 
 void KernelIsolate::Run() {
   if (!FLAG_use_dart_frontend) {
     return;
   }
   // Grab the isolate create callback here to avoid race conditions with tests
   // that change this after Dart_Initialize returns.
   create_callback_ = Isolate::CreateCallback();
   Dart::thread_pool()->Run(new RunKernelTask());
 }
 
 
 void KernelIsolate::InitCallback(Isolate* I) {
   Thread* T = Thread::Current();
   ASSERT(I == T->isolate());
   ASSERT(I != NULL);
   ASSERT(I->name() != NULL);
   if (!FLAG_use_dart_frontend ||
-      (strstr(I->name(), "kernel-service") == NULL)) {
+      (strstr(I->name(), DART_KERNEL_ISOLATE_NAME) == NULL)) {
     // Not kernel isolate.
     return;
   }
   ASSERT(!Exists());
   if (FLAG_trace_kernel) {
-    OS::Print("kernel-service: InitCallback for %s.\n", I->name());
+    OS::Print(DART_KERNEL_ISOLATE_NAME ": InitCallback for %s.\n", I->name());
   }
   SetKernelIsolate(I);
 }
 
 
 bool KernelIsolate::IsKernelIsolate(const Isolate* isolate) {
   MonitorLocker ml(monitor_);
   return isolate == isolate_;
 }
 
 
 bool KernelIsolate::IsRunning() {
   MonitorLocker ml(monitor_);
   return (kernel_port_ != ILLEGAL_PORT) && (isolate_ != NULL);
 }
 
 
 bool KernelIsolate::Exists() {
   MonitorLocker ml(monitor_);
   return isolate_ != NULL;
 }
 
 
 void KernelIsolate::SetKernelIsolate(Isolate* isolate) {
   MonitorLocker ml(monitor_);
   isolate_ = isolate;
 }
 
+
 void KernelIsolate::SetLoadPort(Dart_Port port) {
   MonitorLocker ml(monitor_);
   kernel_port_ = port;
 }
 
+
 void KernelIsolate::FinishedInitializing() {
   MonitorLocker ml(monitor_);
   initializing_ = false;
   ml.NotifyAll();
 }
 
 
 Dart_Port KernelIsolate::WaitForKernelPort() {
   if (!FLAG_use_dart_frontend) {
     return ILLEGAL_PORT;
   }
   MonitorLocker ml(monitor_);
   while (initializing_ && (kernel_port_ == ILLEGAL_PORT)) {
     ml.Wait();
   }
   return kernel_port_;
 }
 
+
+class KernelCompilationRequest {

[kustermann, 2017/01/30 12:14:26]

: public StackResource 

[Vyacheslav Egorov (Google), 2017/01/30 19:34:14]

Done.

+ public:
+  KernelCompilationRequest()
+      : monitor_(new Monitor()),
+        port_(Dart_NewNativePort("kernel-compilation-port",
+                                 &HandleResponse,
+                                 false,
+                                 this)) {
+    result_.status = Dart_KernelCompilationStatus_Unknown;
+    result_.error = NULL;
+    result_.kernel = NULL;
+    result_.kernel_size = 0;
+  }
+
+  ~KernelCompilationRequest() {
+    Dart_CloseNativePort(port_);
+    delete monitor_;
+  }
+
+  Dart_KernelCompilationResult SendAndWaitForResponse(Dart_Port kernel_port,
+                                                      const char* script_uri) {
+    char* script_uri_copy = strdup(script_uri);
+
+    // Build the [null, send_port, script_uri] message for the Kernel isolate:
+    // null tag tells it that request came from this code, instead of Loader
+    // so that it can given a more informative response.
+    Dart_CObject tag;
+    tag.type = Dart_CObject_kNull;
+
+    Dart_CObject send_port;
+    send_port.type = Dart_CObject_kSendPort;
+    send_port.value.as_send_port.id = port_;
+    send_port.value.as_send_port.origin_id = ILLEGAL_PORT;
+
+    Dart_CObject uri;
+    uri.type = Dart_CObject_kString;
+    uri.value.as_string = script_uri_copy;
+
+    static const intptr_t kMessageLen = 3;
+    Dart_CObject* message_arr[kMessageLen] = {&tag, &send_port, &uri};
+
+    Dart_CObject message;
+    message.type = Dart_CObject_kArray;
+    message.value.as_array.length = kMessageLen;
+    message.value.as_array.values = message_arr;
+
+    // Send the message.
+    Dart_PostCObject(kernel_port, &message);
+
+    // Wait for reply to arrive.
+    MonitorLocker ml(monitor_);
+    while (result_.status == Dart_KernelCompilationStatus_Unknown) {
+      ml.Wait();
+    }
+
+    free(script_uri_copy);

[kustermann, 2017/01/30 12:14:28]

Why do you strdup() it first, and free it here. Can't you just pass the pointer
and not free it?

[Vyacheslav Egorov (Google), 2017/01/30 19:34:14]

Done.

+    return result_;
+  }
+
+ private:
+  // Possible responses from the Kernel isolate:
+  //
+  //     [Ok, Uint8List KernelBinary]
+  //     [Error, String error]
+  //     [Crash, String error]
+  //
+  void HandleResponseImpl(Dart_CObject* message) {
+    ASSERT(message->type == Dart_CObject_kArray);
+    ASSERT(message->value.as_array.length >= 1);
+
+    Dart_CObject** response = message->value.as_array.values;
+
+    MonitorLocker ml(monitor_);
+
+    ASSERT(response[0]->type == Dart_CObject_kInt32);
+    result_.status = static_cast<Dart_KernelCompilationStatus>(
+        message->value.as_array.values[0]->value.as_int32);
+
+    if (result_.status == Dart_KernelCompilationStatus_Ok) {
+      ASSERT(response[1]->type == Dart_CObject_kTypedData);
+      ASSERT(response[1]->value.as_typed_data.type == Dart_TypedData_kUint8);
+
+      result_.kernel_size = response[1]->value.as_typed_data.length;
+      result_.kernel = static_cast<uint8_t*>(malloc(result_.kernel_size));
+      memmove(result_.kernel, response[1]->value.as_typed_data.values,
+              result_.kernel_size);
+    } else {
+      ASSERT(result_.status == Dart_KernelCompilationStatus_Crash ||
+             result_.status == Dart_KernelCompilationStatus_Error);
+      // This is an error.
+      ASSERT(response[1]->type == Dart_CObject_kString);
+      result_.error = strdup(response[1]->value.as_string);
+    }
+    ml.NotifyAll();

[siva, 2017/01/24 02:38:02]

Why does it have to do a notifyAll, it appears that we have only one thread
waiting above in SendAndWaitForResponse

[kustermann, 2017/01/30 12:14:26]

Agreed. Notify() should be enough

[Vyacheslav Egorov (Google), 2017/01/30 19:34:14]

Done.

+  }
+
+  static void HandleResponse(Dart_Port dest_port_id,
+                             Dart_CObject* message,
+                             void* peer) {
+    static_cast<KernelCompilationRequest*>(peer)->HandleResponseImpl(message);
+  }
+
+  Monitor* monitor_;
+  Dart_Port port_;
+
+  Dart_KernelCompilationResult result_;

[siva, 2017/01/24 02:38:02]

The boiler plate DISALLOW_* stuff is missing.

[kustermann, 2017/01/30 12:14:28]

I think it can be inherited via StackResource.

[Vyacheslav Egorov (Google), 2017/01/30 19:34:14]

Done.

+};
+
+
+Dart_KernelCompilationResult KernelIsolate::CompileToKernel(
+    const char* script_uri) {
+  // This must be the main script to be loaded. Wait for Kernel isolate
+  // to finish initialization.
+  Dart_Port kernel_port = WaitForKernelPort();
+  if (kernel_port == ILLEGAL_PORT) {
+    Dart_KernelCompilationResult result;
+    result.status = Dart_KernelCompilationStatus_Unknown;
+    result.error = strdup("Error while initializing Kernel isolate");
+    return result;
+  }
+
+  KernelCompilationRequest request;
+  return request.SendAndWaitForResponse(kernel_port, script_uri);
+}
+
+
 #endif  // DART_PRECOMPILED_RUNTIME
 
 }  // namespace dart