DBC: Another allocation fast path

runtime/vm/constants_dbc.h

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef VM_CONSTANTS_DBC_H_
 #define VM_CONSTANTS_DBC_H_
 
 #include "platform/globals.h"
 #include "platform/assert.h"
 #include "platform/utils.h"
@@ skipping 313 matching lines @@
 //
 //    Try allocating an object with tags in PP[D] with no type arguments.
 //    If allocation is successful, the result is stored in FP[rA], and
 //    the next two instructions, which should be the (Allocate class; PopLocal)
 //    slow path are skipped
 //
 //  - AllocateT
 //
 //    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.
 //    SP[-2] is assumed to be a RawArray, SP[-1] to be a smi.
 //
 //  - StoreIndexed rA, rB, rC
 //
 //    Store FP[rC] into array FP[rA] at index FP[rB]. No typechecking is done.
 //    FP[rA] is assumed to be a RawArray, FP[rB] to be a smi.
 //
@@ skipping 113 matching lines @@
 //
 //  - SetFrame A
 //
 //    Reinitialize SP assuming that current frame has size A.
 //    Used to drop temporaries from the stack in the exception handler.
 //
 //  - AllocateContext D
 //
 //    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.
 //
 //  - MoveSpecial rA, D
 //
 //    Copy special values from inside interpreter to FP[rA]. Currently only
 //    used to pass exception object (D = 0) and stack trace object (D = 1) to
 //    catch handler.
 //
@@ skipping 218 matching lines @@
   V(IfDGt,                         A_D, reg, reg, ___) \
   V(IfNeStrictNum,                 A_D, reg, reg, ___) \
   V(IfEqStrictNum,                 A_D, reg, reg, ___) \
   V(IfEqNull,                        A, reg, ___, ___) \
   V(IfNeNull,                        A, reg, ___, ___) \
   V(CreateArrayTOS,                  0, ___, ___, ___) \
   V(CreateArrayOpt,              A_B_C, reg, reg, ___) \
   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) \
   V(StoreIndexedExternalUint8,   A_B_C, reg, reg, reg) \
   V(StoreIndexedOneByteString,   A_B_C, reg, reg, reg) \
   V(StoreIndexedUint32,          A_B_C, reg, reg, reg) \
   V(StoreIndexedFloat64,         A_B_C, reg, reg, reg) \
   V(StoreIndexed8Float64,        A_B_C, reg, reg, reg) \
   V(LoadIndexed,                 A_B_C, reg, reg, reg) \
   V(LoadIndexedUint8,            A_B_C, reg, reg, reg) \
@@ skipping 13 matching lines @@
   V(LoadFieldTOS,                    D, num, ___, ___) \
   V(BooleanNegateTOS,                0, ___, ___, ___) \
   V(BooleanNegate,                 A_D, reg, reg, ___) \
   V(Throw,                           A, num, ___, ___) \
   V(Entry,                       A_B_C, num, num, num) \
   V(EntryOptional,               A_B_C, num, num, num) \
   V(EntryOptimized,                A_D, num, num, ___) \
   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, ___, ___) \
   V(InstantiateTypeArgumentsTOS,   A_D, num, lit, ___) \
   V(InstanceOf,                      A, num, ___, ___) \
   V(AssertAssignable,                D, num, lit, ___) \
   V(AssertBoolean,                   A, num, ___, ___) \
   V(TestSmi,                       A_D, reg, reg, ___) \
   V(TestCids,                      A_D, reg, num, ___) \
   V(CheckSmi,                        A, reg, ___, ___) \
@@ skipping 142 matching lines @@
 
 // After a comparison, the condition NEXT_IS_TRUE means the following
 // instruction is executed if the comparision is true and skipped over overwise.
 // Conidition NEXT_IS_FALSE means the following instruction is executed if the
 // comparison is false and skipped over otherwise.
 enum Condition { NEXT_IS_TRUE, NEXT_IS_FALSE };
 
 }  // namespace dart
 
 #endif  // VM_CONSTANTS_DBC_H_