JIT precompilated snapshots.

runtime/vm/raw_object_snapshot.cc

Index: runtime/vm/raw_object_snapshot.cc
diff --git a/runtime/vm/raw_object_snapshot.cc b/runtime/vm/raw_object_snapshot.cc
index eec25231efd802fd6b598fb917a80a67a9f7dd3f..dd22de0949462e7b51c5a16800e69029da83e237 100644
--- a/runtime/vm/raw_object_snapshot.cc
+++ b/runtime/vm/raw_object_snapshot.cc
@@ -644,13 +644,12 @@ void RawClosureData::WriteTo(SnapshotWriter* writer,
   // Context scope.
   if (ptr()->context_scope_ == Object::empty_context_scope().raw()) {
     writer->WriteVMIsolateObject(kEmptyContextScopeObject);
+  } else if (ptr()->context_scope_->ptr()->is_implicit_ ||
+             (kind == Snapshot::kAppWithJIT)) {
+    writer->WriteObjectImpl(ptr()->context_scope_, kAsInlinedObject);
   } else {
-    if (ptr()->context_scope_->ptr()->is_implicit_) {
-      writer->WriteObjectImpl(ptr()->context_scope_, kAsInlinedObject);
-    } else {
-      // We don't write non implicit context scopes in the snapshot.
-      writer->WriteVMIsolateObject(kNullObject);
-    }
+    // We don't write non implicit context scopes in the snapshot.
+    writer->WriteVMIsolateObject(kNullObject);
   }
 
   // Parent function.
@@ -730,7 +729,7 @@ RawFunction* Function::ReadFrom(SnapshotReader* reader,
     func.set_kind_tag(reader->Read<uint32_t>());
     func.set_token_pos(TokenPosition::SnapshotDecode(token_pos));
     func.set_end_token_pos(TokenPosition::SnapshotDecode(end_token_pos));
-    if (Snapshot::IncludesCode(kind)) {
+    if (kind == Snapshot::kAppNoJIT) {
       func.set_usage_counter(0);
       func.set_deoptimization_counter(0);
       func.set_optimized_instruction_count(0);
@@ -748,12 +747,23 @@ RawFunction* Function::ReadFrom(SnapshotReader* reader,
                        func.raw()->from(), func.raw()->to_snapshot(),
                        kAsReference);
     // Initialize all fields that are not part of the snapshot.
-    if (Snapshot::IncludesCode(kind)) {
+    if (kind == Snapshot::kAppNoJIT) {
       func.ClearICDataArray();
       func.ClearCode();
       // Read the code object and fixup entry point.
       (*reader->CodeHandle()) ^= reader->ReadObjectImpl(kAsInlinedObject);
       func.SetInstructions(*reader->CodeHandle());
+    } else if (kind == Snapshot::kAppWithJIT) {
+      func.ClearICDataArray();

[siva, 2016/05/05 00:08:32]

why do you have to clear the IC data array here we are anyway reading the ic
data and assigning it below.

[rmacnak, 2016/05/05 01:47:03]

ClearICData satisfied assert in ClearCode below.

+      func.ClearCode();

[siva, 2016/05/05 00:08:32]

Ditto question about ClearCode can we do it conditionally based on the code
object we read?

[rmacnak, 2016/05/05 01:47:03]

Yes, that works.

+      (*reader->ArrayHandle()) ^= reader->ReadObjectImpl(kAsReference);
+      func.set_ic_data_array(*reader->ArrayHandle());
+      (*reader->CodeHandle()) ^= reader->ReadObjectImpl(kAsInlinedObject);
+      func.set_unoptimized_code(*reader->CodeHandle());
+      if (!reader->CodeHandle()->IsNull()) {
+        func.SetInstructions(*reader->CodeHandle());
+        func.set_was_compiled(true);
+      }
     } else {
       bool is_optimized = func.usage_counter() != 0;
       if (is_optimized) {
@@ -784,7 +794,7 @@ void RawFunction::WriteTo(SnapshotWriter* writer,
     intptr_t tags = writer->GetObjectTags(ptr()->owner_);
     intptr_t cid = ClassIdTag::decode(tags);
     owner_is_class = (cid == kClassCid);
-    is_in_fullsnapshot =  owner_is_class ?
+    is_in_fullsnapshot = owner_is_class ?
         Class::IsInFullSnapshot(reinterpret_cast<RawClass*>(ptr()->owner_)) :
         PatchClass::IsInFullSnapshot(
             reinterpret_cast<RawPatchClass*>(ptr()->owner_));
@@ -811,7 +821,7 @@ void RawFunction::WriteTo(SnapshotWriter* writer,
     writer->Write<int16_t>(ptr()->num_fixed_parameters_);
     writer->Write<int16_t>(ptr()->num_optional_parameters_);
     writer->Write<uint32_t>(ptr()->kind_tag_);
-    if (Snapshot::IncludesCode(kind)) {
+    if (kind == Snapshot::kAppNoJIT) {
       // Omit fields used to support de/reoptimization.
     } else {
       if (is_optimized) {
@@ -827,15 +837,16 @@ void RawFunction::WriteTo(SnapshotWriter* writer,
     // Write out all the object pointer fields.
     SnapshotWriterVisitor visitor(writer, kAsReference);
     visitor.VisitPointers(from(), to_snapshot());
-    if (Snapshot::IncludesCode(kind)) {
+    if (kind == Snapshot::kAppNoJIT) {
       ASSERT(ptr()->ic_data_array_ == Array::null());
       ASSERT((ptr()->code_ == ptr()->unoptimized_code_) ||
              (ptr()->unoptimized_code_ == Code::null()));
-      // Write out the code object as we are generating a precompiled snapshot.
       writer->WriteObjectImpl(ptr()->code_, kAsInlinedObject);
+    } else if (kind == Snapshot::kAppWithJIT) {
+      writer->WriteObjectImpl(ptr()->ic_data_array_, kAsReference);
+      writer->WriteObjectImpl(ptr()->unoptimized_code_, kAsInlinedObject);
     } else if (is_optimized) {
-      // Write out the ic data array as the function is optimized or
-      // we are generating a precompiled snapshot.
+      // Write out the ic data array as the function is optimized.
       writer->WriteObjectImpl(ptr()->ic_data_array_, kAsReference);
     }
   } else {
@@ -922,6 +933,9 @@ void RawField::WriteTo(SnapshotWriter* writer,
       // For precompiled static fields, the value was already reset and
       // initializer_ now contains a Function.
       writer->WriteObjectImpl(ptr()->value_.static_value_, kAsReference);
+    } else if (Field::ConstBit::decode(ptr()->kind_bits_)) {
+      // Do not reset const fields.
+      writer->WriteObjectImpl(ptr()->value_.static_value_, kAsReference);
     } else {
       // Otherwise, for static fields we write out the initial static value.
       writer->WriteObjectImpl(ptr()->initializer_.saved_value_, kAsReference);
@@ -1435,9 +1449,18 @@ void RawCode::WriteTo(SnapshotWriter* writer,
 
   intptr_t pointer_offsets_length =
       Code::PtrOffBits::decode(ptr()->state_bits_);
-  if (pointer_offsets_length != 0) {
-    // Should only be IA32.
-    FATAL("Cannot serialize code with embedded pointers");
+  // Cannot serialize code with embedded pointers (IA32).
+  ASSERT(pointer_offsets_length == 0);

[siva, 2016/05/05 00:08:32]

Why did you change this to an assert from FATAL?

[rmacnak, 2016/05/05 01:47:03]

Was thinking the fatals on --precompilation would hit first, but that won't
happen for a JIT snapshot.

+  if (kind == Snapshot::kAppNoJIT) {
+    // No disabled code in precompilation.
+    ASSERT(ptr()->instructions_ == ptr()->active_instructions_);
+  } else {
+    ASSERT(kind == Snapshot::kAppWithJIT);
+    // We never include optimized code in JIT precompilation. Deoptimization
+    // requires code patching and we cannot patch code that is shared between
+    // isolates and should not mutate memory allocated by the embedder.
+    bool is_optimized = Code::PtrOffBits::decode(ptr()->state_bits_);
+    ASSERT(!is_optimized);

[siva, 2016/05/05 00:08:32]

shouldn't this ASSERT be a FATAL instead?

[rmacnak, 2016/05/05 01:47:03]

Done.

   }
 
   // Write out the serialization header value for this object.
@@ -1450,9 +1473,6 @@ void RawCode::WriteTo(SnapshotWriter* writer,
   // Write out all the non object fields.
   writer->Write<int32_t>(ptr()->state_bits_);
 
-  // No disabled code in precompilation.
-  ASSERT(ptr()->instructions_ == ptr()->active_instructions_);
-
   RawInstructions* instr = ptr()->instructions_;
   int32_t text_offset = writer->GetInstructionsId(instr, this);
   writer->Write<int32_t>(text_offset);
@@ -1932,6 +1952,19 @@ RawContextScope* ContextScope::ReadFrom(SnapshotReader* reader,
     context_scope.SetContextIndexAt(0, 0);
     context_scope.SetContextLevelAt(0, 0);
     return context_scope.raw();
+  } else if (kind == Snapshot::kAppWithJIT) {
+    int32_t num_vars = reader->Read<int32_t>();
+
+    ContextScope& context_scope = ContextScope::ZoneHandle();

[siva, 2016/05/05 00:08:32]

ZoneHandle(zone());

[rmacnak, 2016/05/05 01:47:03]

Done.

+    context_scope = reader->NewContextScope(num_vars);
+    context_scope.set_is_implicit(false);
+    reader->AddBackRef(object_id, &context_scope, kIsDeserialized);
+
+    READ_OBJECT_FIELDS(context_scope,
+                       context_scope.raw()->from(),
+                       context_scope.raw()->to(num_vars),
+                       kAsInlinedObject);
+    return context_scope.raw();
   }
   UNREACHABLE();
   return NULL;
@@ -1962,6 +1995,23 @@ void RawContextScope::WriteTo(SnapshotWriter* writer,
     writer->WriteObjectImpl(var->type, kAsInlinedObject);
 
     return;
+  } else if (kind == Snapshot::kAppWithJIT) {
+    // Write out the serialization header value for this object.
+    writer->WriteInlinedObjectHeader(object_id);
+
+    // Write out the class and tags information.
+    writer->WriteVMIsolateObject(kContextScopeCid);
+    writer->WriteTags(writer->GetObjectTags(this));
+
+    // Write out is_implicit flag for the context scope.
+    writer->Write<bool>(false);
+    int32_t num_vars = ptr()->num_variables_;
+    writer->Write<int32_t>(num_vars);
+
+    SnapshotWriterVisitor visitor(writer, kAsInlinedObject);
+    visitor.VisitPointers(from(), to(num_vars));
+
+    return;
   }
   UNREACHABLE();
 }