DBC: Another allocation fast path

runtime/vm/constants_dbc.h

Index: runtime/vm/constants_dbc.h
diff --git a/runtime/vm/constants_dbc.h b/runtime/vm/constants_dbc.h
index c5dbe04f52f287ff717c2cd9661c9446b60ced42..4d9c29ab2962e88bd2f3f5d8dedaa09ab8ab0738 100644
--- a/runtime/vm/constants_dbc.h
+++ b/runtime/vm/constants_dbc.h
@@ -331,6 +331,13 @@ namespace dart {
 //
 //    Allocate object of class SP[0] with type arguments SP[-1].
 //
+//  - AllocateTOpt rA, D
+//
+//    Similar to AllocateOpt with the difference that the offset of the
+//    type arguments in the resulting object is taken from the D field of the
+//    following Nop instruction, and on success 4 instructions are skipped and
+//    the object at the top of the stack is popped.
+//
 //  - StoreIndexedTOS
 //
 //    Store SP[0] into array SP[-2] at index SP[-1]. No typechecking is done.
@@ -464,6 +471,12 @@ namespace dart {
 //
 //    Allocate Context object assuming for D context variables.
 //
+//  - AllocateUninitializedContext rA, D
+//
+//    Allocates an uninitialized context for D variables, and places the result
+//    in FP[rA]. On success, skips the next 2 instructions, which should be the
+//    slow path (AllocateContext D; PopLocal rA).
+//
 //  - CloneContext
 //
 //    Clone context stored in TOS.
@@ -702,6 +715,7 @@ namespace dart {
   V(Allocate,                        D, lit, ___, ___) \
   V(AllocateT,                       0, ___, ___, ___) \
   V(AllocateOpt,                   A_D, reg, lit, ___) \
+  V(AllocateTOpt,                  A_D, reg, lit, ___) \
   V(StoreIndexedTOS,                 0, ___, ___, ___) \
   V(StoreIndexed,                A_B_C, reg, reg, reg) \
   V(StoreIndexedUint8,           A_B_C, reg, reg, reg) \
@@ -735,6 +749,7 @@ namespace dart {
   V(Frame,                           D, num, ___, ___) \
   V(SetFrame,                        A, num, ___, num) \
   V(AllocateContext,                 D, num, ___, ___) \
+  V(AllocateUninitializedContext,  A_D, reg, num, ___) \
   V(CloneContext,                    0, ___, ___, ___) \
   V(MoveSpecial,                   A_D, reg, num, ___) \
   V(InstantiateType,                 D, lit, ___, ___) \