VM: Precompiled rodata snapshot.

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 87305bab2a32865adaf025b431415dc28f8b3651..c48b9cd6a3aa508ff1c7ed2ccfb146d474948166 100644
--- a/runtime/vm/raw_object_snapshot.cc
+++ b/runtime/vm/raw_object_snapshot.cc
@@ -1345,7 +1345,11 @@ RawInstructions* Instructions::ReadFrom(SnapshotReader* reader,
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
+#ifdef DEBUG
   intptr_t full_tags = static_cast<uword>(reader->Read<intptr_t>());
+#else
+  intptr_t full_tags = 0;  // unused in release mode
+#endif
   intptr_t offset = reader->Read<int32_t>();
   Instructions& result =
       Instructions::ZoneHandle(reader->zone(),
@@ -1367,6 +1371,7 @@ void RawInstructions::WriteTo(SnapshotWriter* writer,
   writer->WriteVMIsolateObject(kInstructionsCid);
   writer->WriteTags(writer->GetObjectTags(this));
 
+#ifdef DEBUG
   // Instructions will be written pre-marked and in the VM heap. Write out
   // the tags we expect to find when reading the snapshot for a sanity check
   // that our offsets/alignment didn't get out of sync.
@@ -1374,6 +1379,7 @@ void RawInstructions::WriteTo(SnapshotWriter* writer,
   written_tags = RawObject::VMHeapObjectTag::update(true, written_tags);
   written_tags = RawObject::MarkBit::update(true, written_tags);
   writer->Write<intptr_t>(written_tags);
+#endif
 
   writer->Write<int32_t>(writer->GetInstructionsId(this));
 }
@@ -1511,19 +1517,11 @@ RawPcDescriptors* PcDescriptors::ReadFrom(SnapshotReader* reader,
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
-  const int32_t length = reader->Read<int32_t>();
-  PcDescriptors& result =
-      PcDescriptors::ZoneHandle(reader->zone(),
-                                NEW_OBJECT_WITH_LEN(PcDescriptors, length));
+  intptr_t offset = reader->Read<int32_t>();
+  PcDescriptors& result = PcDescriptors::ZoneHandle(reader->zone());
+  result ^= reader->GetObjectAt(offset);
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
-  if (result.Length() > 0) {
-    NoSafepointScope no_safepoint;
-    intptr_t len = result.Length();
-    uint8_t* data = result.UnsafeMutableNonPointer(result.raw_ptr()->data());
-    reader->ReadBytes(data, len);
-  }
-
   return result.raw();
 }
 
@@ -1539,12 +1537,8 @@ void RawPcDescriptors::WriteTo(SnapshotWriter* writer,
   writer->WriteInlinedObjectHeader(object_id);
   writer->WriteIndexedObject(kPcDescriptorsCid);
   writer->WriteTags(writer->GetObjectTags(this));
-  writer->Write<int32_t>(ptr()->length_);
-  if (ptr()->length_ > 0) {
-    intptr_t len = ptr()->length_;
-    uint8_t* data = reinterpret_cast<uint8_t*>(ptr()->data());
-    writer->WriteBytes(data, len);
-  }
+
+  writer->Write<int32_t>(writer->GetObjectId(this));
 }
 
 
@@ -1556,22 +1550,11 @@ RawStackmap* Stackmap::ReadFrom(SnapshotReader* reader,
   ASSERT(reader->snapshot_code());
   ASSERT(kind == Snapshot::kFull);
 
-  const int32_t length = reader->Read<int32_t>();
-  Stackmap& result =
-      Stackmap::ZoneHandle(reader->zone(),
-                           reader->NewStackmap(length));
+  intptr_t offset = reader->Read<int32_t>();
+  Stackmap& result = Stackmap::ZoneHandle(reader->zone());
+  result ^= reader->GetObjectAt(offset);
   reader->AddBackRef(object_id, &result, kIsDeserialized);
 
-  result.SetRegisterBitCount(reader->Read<int32_t>());
-  result.SetPcOffset(reader->Read<uint32_t>());
-
-  if (length > 0) {
-    NoSafepointScope no_safepoint;
-    intptr_t len = (result.Length() + 7) / 8;
-    uint8_t* data = result.UnsafeMutableNonPointer(result.raw_ptr()->data());
-    reader->ReadBytes(data, len);
-  }
-
   return result.raw();
 }
 
@@ -1588,14 +1571,7 @@ void RawStackmap::WriteTo(SnapshotWriter* writer,
   writer->WriteIndexedObject(kStackmapCid);
   writer->WriteTags(writer->GetObjectTags(this));
 
-  writer->Write<int32_t>(ptr()->length_);
-  writer->Write<int32_t>(ptr()->register_bit_count_);
-  writer->Write<uint32_t>(ptr()->pc_offset_);
-  if (ptr()->length_ > 0) {
-    intptr_t len = (ptr()->length_ + 7) / 8;
-    uint8_t* data = reinterpret_cast<uint8_t*>(ptr()->data());
-    writer->WriteBytes(data, len);
-  }
+  writer->Write<int32_t>(writer->GetObjectId(this));
 }