Adapt Danno's Track Allocation Info idea to fast literals. When allocating a literal array,

src/arm/macro-assembler-arm.h

Index: src/arm/macro-assembler-arm.h
diff --git a/src/arm/macro-assembler-arm.h b/src/arm/macro-assembler-arm.h
index 454e64523b981955756c1dbf456cd85edfa841be..d364248a4cb0ea13b07b6cfddb768471a0ab9bd6 100644
--- a/src/arm/macro-assembler-arm.h
+++ b/src/arm/macro-assembler-arm.h
@@ -1309,6 +1309,13 @@ class MacroAssembler: public Assembler {
   // in r0.  Assumes that any other register can be used as a scratch.
   void CheckEnumCache(Register null_value, Label* call_runtime);
 
+  // AllocationSiteInfo support. Arrays may have an associated
+  // AllocationSiteInfo object that can be checked for in order to pretransition
+  // to another type.
+  // On entry, r2 should point to the array object. r4 gets clobbered.
+  // If allocation info is present, jump to allocation_info_present
+  void PerformAllocationSiteInfoCheck(Label* allocation_info_present);

[danno, 2013/01/04 08:50:55]

Pass the two registers that are used into this function like in other functions
in the macro assembler (for example, take a look at InitializeNewString). Then
specify r2 and r4 at the calling site. Same on other platforms, too.

You might want to make the name here and on other platforms mention arrays, too,
since this routine only works for JSArrays. For example,
TestJSArrayForAllocationSiteInfo

[mvstanton, 2013/01/04 12:07:52]

Done.

+
  private:
   void CallCFunctionHelper(Register function,
                            int num_reg_arguments,