MIPS: Introduce basic type feedback for for-in statements to avoid deopts.

src/mips/full-codegen-mips.cc

Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index e259fc460033025342f66e848d4643112b78837c..c5ef2ccbf7401adf356028b4764d4e0e0ae0d532 100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -1015,6 +1015,16 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   // We got a fixed array in register v0. Iterate through that.
   Label non_proxy;
   __ bind(&fixed_array);
+
+  Handle<JSGlobalPropertyCell> cell =
+      isolate()->factory()->NewJSGlobalPropertyCell(
+          Handle<Object>(
+              Smi::FromInt(TypeFeedbackCells::kForInFastCaseMarker)));
+  RecordTypeFeedbackCell(stmt->PrepareId(), cell);
+  __ LoadHeapObject(a1, cell);
+  __ li(a2, Operand(Smi::FromInt(TypeFeedbackCells::kForInSlowCaseMarker)));
+  __ sw(a2, FieldMemOperand(a1, JSGlobalPropertyCell::kValueOffset));
+
   __ li(a1, Operand(Smi::FromInt(1)));  // Smi indicates slow check
   __ lw(a2, MemOperand(sp, 0 * kPointerSize));  // Get enumerated object
   STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);