Toward precompiled snapshots.

runtime/vm/native_api_impl.cc

Index: runtime/vm/native_api_impl.cc
diff --git a/runtime/vm/native_api_impl.cc b/runtime/vm/native_api_impl.cc
index a6688976e9924ee175f08f01754ad6959514374d..b0189366eb2261d31cde055071f089ec40ddbde4 100644
--- a/runtime/vm/native_api_impl.cc
+++ b/runtime/vm/native_api_impl.cc
@@ -15,6 +15,8 @@
 
 namespace dart {
 
+DECLARE_FLAG(bool, load_deferred_eagerly);
+
 // --- Message sending/receiving from native code ---
 
 static uint8_t* allocator(uint8_t* ptr, intptr_t old_size, intptr_t new_size) {
@@ -103,6 +105,12 @@ DART_EXPORT Dart_Handle Dart_CompileAll() {
   return result;
 }
 
+static uint8_t* ApiReallocate(uint8_t* ptr,
+                              intptr_t old_size,
+                              intptr_t new_size) {
+  return Api::TopScope(Isolate::Current())->zone()->Realloc<uint8_t>(
+      ptr, old_size, new_size);
+}
 
 DART_EXPORT Dart_Handle Dart_Precompile() {
   Isolate* isolate = Isolate::Current();
@@ -116,4 +124,49 @@ DART_EXPORT Dart_Handle Dart_Precompile() {
   return result;
 }
 
+DART_EXPORT Dart_Handle Dart_CreatePrecompiledSnapshot(
+    uint8_t** vm_isolate_snapshot_buffer,
+    intptr_t* vm_isolate_snapshot_size,
+    uint8_t** isolate_snapshot_buffer,
+    intptr_t* isolate_snapshot_size,
+    uint8_t** instructions_snapshot_buffer,
+    intptr_t* instructions_snapshot_size) {
+  ASSERT(FLAG_load_deferred_eagerly);

[siva, 2015/09/01 20:58:49]

instead of asserting like this why not do what we do for
generate_script_snapshots in main.cc

  if (generate_script_snapshot) {
    vm_options.AddArgument("--load_deferred_eagerly");
  }

[rmacnak, 2015/09/01 23:43:47]

That's in the embedder before loading. Here it is too late.

When the embedder enabled --precompile it caused --load_deferred_eagerly to also
be enabled.

+  Thread* thread = Thread::Current();
+  Isolate* isolate = thread->isolate();
+  DARTSCOPE(isolate);
+  if (vm_isolate_snapshot_buffer != NULL &&
+      vm_isolate_snapshot_size == NULL) {
+    RETURN_NULL_ERROR(vm_isolate_snapshot_size);
+  }
+  if (isolate_snapshot_buffer == NULL) {
+    RETURN_NULL_ERROR(isolate_snapshot_buffer);
+  }
+  if (isolate_snapshot_size == NULL) {
+    RETURN_NULL_ERROR(isolate_snapshot_size);
+  }
+  if (instructions_snapshot_buffer == NULL) {
+    RETURN_NULL_ERROR(instructions_snapshot_buffer);
+  }
+  if (instructions_snapshot_size == NULL) {
+    RETURN_NULL_ERROR(instructions_snapshot_size);
+  }
+  // Finalize all classes if needed.
+  Dart_Handle state = Api::CheckAndFinalizePendingClasses(isolate);
+  if (::Dart_IsError(state)) {
+    return state;
+  }
+  isolate->heap()->CollectAllGarbage();
+  PrecompiledSnapshotWriter writer(vm_isolate_snapshot_buffer,
+                                   isolate_snapshot_buffer,
+                                   instructions_snapshot_buffer,
+                                   ApiReallocate);
+  writer.WriteFullSnapshot();
+  *vm_isolate_snapshot_size = writer.VmIsolateSnapshotSize();

[siva, 2015/09/01 20:58:49]

if vm_isoolate_snapshot_buffer is NULL this could lead to a crash as you allow
vm_isolate_snapshot_size to be NULL

[rmacnak, 2015/09/01 23:43:47]

Now requiring vm_isolate_snapshot_buffer to be non-NULL.

+  *isolate_snapshot_size = writer.IsolateSnapshotSize();
+  *instructions_snapshot_size = writer.InstructionsSnapshotSize();
+
+  return Api::Success();
+}
+
 }  // namespace dart