Landing: Write protect executable pages in the VM.

runtime/vm/assembler_x64.h

Index: runtime/vm/assembler_x64.h
diff --git a/runtime/vm/assembler_x64.h b/runtime/vm/assembler_x64.h
index 0e1f2a6f8c0ef8166f322e488cf3c4a1bcfd3e72..feee3ade45f00537464e7cc57cb2ee159aa22ccf 100644
--- a/runtime/vm/assembler_x64.h
+++ b/runtime/vm/assembler_x64.h
@@ -758,6 +758,13 @@ class Assembler : public ValueObject {
 
   intptr_t CodeSize() const { return buffer_.Size(); }
   intptr_t prologue_offset() const { return prologue_offset_; }
+
+  // Count the fixups that produce a pointer offset, without processing
+  // the fixups.
+  intptr_t CountPointerOffsets() const {
+    return buffer_.CountPointerOffsets();

[Ivan Posva, 2014/02/03 05:44:35]

Does x64 really create pointer offsets or are all pointers loaded through the
pool pointer?

[Florian Schneider, 2014/02/10 11:56:17]

Possibly yes, if CanLoadImmediateFromPool return false, there maybe immediates
in the generated code.

+  }
+
   const ZoneGrowableArray<intptr_t>& GetPointerOffsets() const {
     return buffer_.pointer_offsets();
   }