DBC: Eager deoptimization and CheckSmi instruction.

runtime/vm/intermediate_language_dbc.cc

Index: runtime/vm/intermediate_language_dbc.cc
diff --git a/runtime/vm/intermediate_language_dbc.cc b/runtime/vm/intermediate_language_dbc.cc
index 4af998e6a78edb5d9df89bc7aea2ed1ca7584bb1..148a98ab93e2a419684cd9576f2a9ee2b8869611 100644
--- a/runtime/vm/intermediate_language_dbc.cc
+++ b/runtime/vm/intermediate_language_dbc.cc
@@ -108,7 +108,6 @@ DECLARE_FLAG(int, optimization_counter_threshold);
   M(UnboxInteger32)                                                            \
   M(CheckedSmiOp)                                                              \
   M(CheckArrayBound)                                                           \
-  M(CheckSmi)                                                                  \
   M(CheckClassId)                                                              \
   M(CheckClass)                                                                \
   M(BinarySmiOp)                                                               \
@@ -850,8 +849,12 @@ Representation LoadIndexedInstr::representation() const {
 Representation StoreIndexedInstr::RequiredInputRepresentation(
     intptr_t idx) const {
   // Array can be a Dart object or a pointer to external data.
-  if (idx == 0)  return kNoRepresentation;  // Flexible input representation.
-  if (idx == 1) return kTagged;  // Index is a smi.
+  if (idx == 0) {
+    return kNoRepresentation;  // Flexible input representation.
+  }
+  if (idx == 1) {
+    return kTagged;  // Index is a smi.
+  }
   ASSERT(idx == 2);
   switch (class_id_) {
     case kArrayCid:
@@ -903,6 +906,14 @@ void Environment::DropArguments(intptr_t argc) {
 }
 
 
+EMIT_NATIVE_CODE(CheckSmi, 1) {
+  __ CheckSmi(locs()->in(0).reg());
+  compiler->AddDeoptWithoutStub(deopt_id(),
+                                ICData::kDeoptCheckSmi,
+                                licm_hoisted_ ? ICData::kHoisted : 0);
+  __ Deopt(0, deopt_id());

[Vyacheslav Egorov (Google), 2016/06/09 15:09:06]

I would prefer to write this as 

compiler->EmitDeopt(deopt_id(),
                    ICData::kDeoptCheckSmi,
                    licm_hoisted_ ? ICData::kHoisted : 0);

and have Deopt instruction be generated and pc recorded in a single place.

[zra, 2016/06/09 16:42:23]

Done.

+}
+
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_DBC