Refactor snapshots pieces to include a section for loading instructions into the heap of a regular …

runtime/vm/gc_sweeper.cc

Index: runtime/vm/gc_sweeper.cc
diff --git a/runtime/vm/gc_sweeper.cc b/runtime/vm/gc_sweeper.cc
index f779b49646d417306074d3a0e671537731b4ac14..609afb9aa9e9a0f4dcfef893afdbda553b8fe297 100644
--- a/runtime/vm/gc_sweeper.cc
+++ b/runtime/vm/gc_sweeper.cc
@@ -16,6 +16,11 @@
 namespace dart {
 
 bool GCSweeper::SweepPage(HeapPage* page, FreeList* freelist, bool locked) {
+  if (page->embedder_allocated()) {
+    // Don't clear mark bits.
+    return true;
+  }

[siva, 2017/01/20 22:53:54]

I am wondering if it would make it more clear if we choose
to use 4 types of pages
kData, kExecutable, kReadOnlyData and kReadOnlyExecutable

This could then be
if (page->IsReadOnly()) {
  return true;
}

where Readonly is one of kReadOnlyData or kReadOnlyExecutable

+
   // Keep track whether this page is still in use.
   bool in_use = false;