Avoid jumping to the runtime for ForInFilter

src/full-codegen/ia32/full-codegen-ia32.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_IA32
 
 #include "src/ast/scopes.h"
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
 #include "src/codegen.h"
@@ skipping 995 matching lines @@
   __ push(Immediate(Smi::FromInt(0)));  // Initial index.
 
   // Generate code for doing the condition check.
   __ bind(&loop);
   SetExpressionAsStatementPosition(stmt->each());
 
   __ mov(eax, Operand(esp, 0 * kPointerSize));  // Get the current index.
   __ cmp(eax, Operand(esp, 1 * kPointerSize));  // Compare to the array length.
   __ j(above_equal, loop_statement.break_label());
 
-  // Get the current entry of the array into register ebx.
+  // Get the current entry of the array into register eax.
   __ mov(ebx, Operand(esp, 2 * kPointerSize));
-  __ mov(ebx, FieldOperand(ebx, eax, times_2, FixedArray::kHeaderSize));
+  __ mov(eax, FieldOperand(ebx, eax, times_2, FixedArray::kHeaderSize));
 
   // Get the expected map from the stack or a smi in the
   // permanent slow case into register edx.
   __ mov(edx, Operand(esp, 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;
-  __ mov(ecx, Operand(esp, 4 * kPointerSize));
-  __ cmp(edx, FieldOperand(ecx, HeapObject::kMapOffset));
+  __ mov(ebx, Operand(esp, 4 * kPointerSize));
+  __ cmp(edx, FieldOperand(ebx, HeapObject::kMapOffset));
   __ j(equal, &update_each, Label::kNear);
 
   // We need to filter the key, record slow-path here.
   int const vector_index = SmiFromSlot(slot)->value();
   __ EmitLoadTypeFeedbackVector(edx);
   __ mov(FieldOperand(edx, FixedArray::OffsetOfElementAt(vector_index)),
          Immediate(TypeFeedbackVector::MegamorphicSentinel(isolate())));
 
-  // Convert the entry to a string or null if it isn't a property
-  // anymore. If the property has been removed while iterating, we
-  // just skip it.
-  __ push(ecx);  // Enumerable.
-  __ push(ebx);  // Current entry.
-  __ CallRuntime(Runtime::kForInFilter);
+  // eax contains the key.  The receiver in ebx 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);
-  __ cmp(eax, isolate()->factory()->undefined_value());
-  __ j(equal, loop_statement.continue_label());
-  __ mov(ebx, eax);
+  __ JumpIfRoot(result_register(), Heap::kUndefinedValueRootIndex,
+                loop_statement.continue_label());
 
   // Update the 'each' property or variable from the possibly filtered
-  // entry in register ebx.
+  // entry in register eax.
   __ bind(&update_each);
-  __ mov(result_register(), ebx);
   // 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 2614 matching lines @@
       isolate->builtins()->OnStackReplacement()->entry(),
       Assembler::target_address_at(call_target_address, unoptimized_code));
   return ON_STACK_REPLACEMENT;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_IA32