Avoid jumping to the runtime for ForInFilter

src/full-codegen/mips/full-codegen-mips.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if V8_TARGET_ARCH_MIPS
 
 // Note on Mips implementation:
 //
 // The result_register() for mips is the 'v0' register, which is defined
 // by the ABI to contain function return values. However, the first
@@ skipping 1060 matching lines @@
 
   // Generate code for doing the condition check.
   __ bind(&loop);
   SetExpressionAsStatementPosition(stmt->each());
 
   // Load the current count to a0, load the length to a1.
   __ lw(a0, MemOperand(sp, 0 * kPointerSize));
   __ lw(a1, MemOperand(sp, 1 * kPointerSize));
   __ Branch(loop_statement.break_label(), hs, a0, Operand(a1));
 
-  // Get the current entry of the array into register a3.
+  // Get the current entry of the array into result_register.
   __ lw(a2, MemOperand(sp, 2 * kPointerSize));
   __ Addu(a2, a2, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
   __ Lsa(t0, a2, a0, kPointerSizeLog2 - kSmiTagSize);
-  __ lw(a3, MemOperand(t0));  // Current entry.
+  __ lw(result_register(), MemOperand(t0));  // Current entry.
 
   // Get the expected map from the stack or a smi in the
   // permanent slow case into register a2.
   __ lw(a2, MemOperand(sp, 3 * kPointerSize));
 
   // Check if the expected map still matches that of the enumerable.
   // If not, we may have to filter the key.
   Label update_each;
   __ lw(a1, MemOperand(sp, 4 * kPointerSize));
   __ lw(t0, FieldMemOperand(a1, HeapObject::kMapOffset));
   __ Branch(&update_each, eq, t0, Operand(a2));
 
   // We need to filter the key, record slow-path here.
   int const vector_index = SmiFromSlot(slot)->value();
-  __ EmitLoadTypeFeedbackVector(a0);
+  __ EmitLoadTypeFeedbackVector(a3);
   __ li(a2, Operand(TypeFeedbackVector::MegamorphicSentinel(isolate())));
-  __ sw(a2, FieldMemOperand(a0, FixedArray::OffsetOfElementAt(vector_index)));
+  __ sw(a2, FieldMemOperand(a3, FixedArray::OffsetOfElementAt(vector_index)));
 
-  // Convert the entry to a string or (smi) 0 if it isn't a property
-  // any more. If the property has been removed while iterating, we
-  // just skip it.
-  __ Push(a1, a3);  // Enumerable and current entry.
-  __ CallRuntime(Runtime::kForInFilter);
+  __ mov(a0, result_register());
+  // a0 contains the key. The receiver in a1 is the second argument to the
+  // ForInFilterStub. ForInFilter returns undefined if the receiver doesn't
+  // have the key or returns the name-converted key.
+  ForInFilterStub filter_stub(isolate());
+  __ CallStub(&filter_stub);
+  RestoreContext();
   PrepareForBailoutForId(stmt->FilterId(), BailoutState::TOS_REGISTER);
-  __ mov(a3, result_register());
   __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
-  __ Branch(loop_statement.continue_label(), eq, a3, Operand(at));
+  __ Branch(loop_statement.continue_label(), eq, result_register(),
+            Operand(at));
 
   // Update the 'each' property or variable from the possibly filtered
-  // entry in register a3.
+  // entry in the result_register.
   __ bind(&update_each);
-  __ mov(result_register(), a3);
   // Perform the assignment as if via '='.
   { EffectContext context(this);
     EmitAssignment(stmt->each(), stmt->EachFeedbackSlot());
     PrepareForBailoutForId(stmt->AssignmentId(), BailoutState::NO_REGISTERS);
   }
 
   // Both Crankshaft and Turbofan expect BodyId to be right before stmt->body().
   PrepareForBailoutForId(stmt->BodyId(), BailoutState::NO_REGISTERS);
   // Generate code for the body of the loop.
   Visit(stmt->body());
@@ skipping 2659 matching lines @@
          reinterpret_cast<uint32_t>(
              isolate->builtins()->OnStackReplacement()->entry()));
   return ON_STACK_REPLACEMENT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_MIPS