Deoptimization can occur at Dart calls (includes native calls to C) but not at runtime calls. This …

runtime/vm/code_descriptors.cc

Index: runtime/vm/code_descriptors.cc
===================================================================
--- runtime/vm/code_descriptors.cc	(revision 11533)
+++ runtime/vm/code_descriptors.cc	(working copy)
@@ -4,6 +4,8 @@
 
 #include "vm/code_descriptors.h"
 
+#include "vm/code_generator.h"
+
 namespace dart {
 
 void DescriptorList::AddDescriptor(PcDescriptors::Kind kind,
@@ -21,15 +23,17 @@
 }
 
 
-void DescriptorList::AddDeoptInfo(intptr_t pc_offset,
-                                  intptr_t deopt_id,
-                                  intptr_t token_index,
-                                  intptr_t deopt_array_index) {
+void DescriptorList::AddDeoptIndex(intptr_t pc_offset,
+                                   intptr_t deopt_id,
+                                   intptr_t deopt_reason,
+                                   intptr_t deopt_array_index) {
   struct PcDesc data;
   data.pc_offset = pc_offset;
   data.kind = PcDescriptors::kDeoptIndex;
   data.deopt_id = deopt_id;
-  data.token_index = token_index;
+  // Token index is used for deopt reason.
+  ASSERT((kDeoptUnknown <= deopt_reason) && (deopt_reason < kDeoptNumReasons));
+  data.token_index = deopt_reason;

[siva, 2012/08/30 01:37:30]

overloading token_index field as deopt_reason can be a bit confusing when
reading code.

I am wondering if it would make the code more readable if we called the field
data and added accessor functions
SetTokenIndex(intptr_t value);
intptr_t TokenIndex();
SetDeoptReason(intptr_t value);
intptr_t DeoptReason();

and used these accessor functions.

[srdjan, 2012/08/30 17:16:16]

Done.

   // Try_index is reused for deopt_array_index.
   data.try_index = deopt_array_index;
   list_.Add(data);