VM: Array bounds checks that don't deoptimize for precompiled code.

runtime/vm/intermediate_language_dbc.cc

 // 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_DBC.
 #if defined(TARGET_ARCH_DBC)
 
 #include "vm/intermediate_language.h"
 
 #include "vm/cpu.h"
@@ skipping 47 matching lines @@
   M(UnboxInteger32)                                                            \
 
 // List of instructions that are not used by DBC.
 // Things we aren't planning to implement for DBC:
 // - Unboxed SIMD,
 // - Unboxed Mint,
 // - Optimized RegExps,
 // - Precompilation.
 #define FOR_EACH_UNREACHABLE_INSTRUCTION(M)                                    \
   M(CaseInsensitiveCompareUC16)                                                \
+  M(GenericCheckBound)                                                         \
   M(GrowRegExpStack)                                                           \
   M(IndirectGoto)                                                              \
   M(MintToDouble)                                                              \
   M(BinaryMintOp)                                                              \
   M(ShiftMintOp)                                                               \
   M(UnaryMintOp)                                                               \
   M(BinaryFloat32x4Op)                                                         \
   M(Simd32x4Shuffle)                                                           \
   M(Simd32x4ShuffleMix)                                                        \
   M(Simd32x4GetSignMask)                                                       \
@@ skipping 1350 matching lines @@
                                        BranchInstr* branch) {
   BranchLabels labels = compiler->CreateBranchLabels(branch);
   Condition true_condition = EmitComparisonCode(compiler, labels);
   EmitBranchOnCondition(compiler, true_condition, labels);
 }
 
 
 EMIT_NATIVE_CODE(CheckArrayBound, 2) {
   const Register length = locs()->in(kLengthPos).reg();
   const Register index = locs()->in(kIndexPos).reg();
+  const intptr_t index_cid = this->index()->Type()->ToCid();
+  if (index_cid != kSmiCid) {
+    __ CheckSmi(index);
+    compiler->EmitDeopt(deopt_id(),
+                        ICData::kDeoptCheckArrayBound,
+                        (generalized_ ? ICData::kGeneralized : 0) |
+                        (licm_hoisted_ ? ICData::kHoisted : 0));
+  }
   __ IfULe(length, index);
   compiler->EmitDeopt(deopt_id(),
                       ICData::kDeoptCheckArrayBound,
                       (generalized_ ? ICData::kGeneralized : 0) |
                       (licm_hoisted_ ? ICData::kHoisted : 0));
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_DBC