Remember all deopt reasons in ic_data, not just the last one.

runtime/vm/code_descriptors.h

Index: runtime/vm/code_descriptors.h
===================================================================
--- runtime/vm/code_descriptors.h	(revision 35415)
+++ runtime/vm/code_descriptors.h	(working copy)
@@ -19,12 +19,13 @@
     intptr_t pc_offset;        // PC offset value of the descriptor.
     PcDescriptors::Kind kind;  // Descriptor kind (kDeopt, kOther).
     intptr_t deopt_id;         // Deoptimization id.
-    intptr_t data;             // Token position or deopt rason.
+    intptr_t data;             // Token position or deopt reason.
     intptr_t try_index;        // Try block index of PC or deopt array index.
     void SetTokenPos(intptr_t value) { data = value; }
     intptr_t TokenPos() const { return data; }
     void SetDeoptReason(DeoptReasonId value) { data = value; }
     DeoptReasonId DeoptReason() const {
+      ASSERT(static_cast<uword>(data) < kDeoptNumReasons);

[Ivan Posva, 2014/04/25 20:59:22]

Can we change this into a compile time assert?

[regis, 2014/04/25 23:38:28]

The value of 'data' is not known at compile time.

       return static_cast<DeoptReasonId>(data);
     }
   };