Implement for-in loop for proxies.

src/x64/full-codegen-x64.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 872 matching lines @@
   Label convert, done_convert;
   __ JumpIfSmi(rax, &convert);
   __ CmpObjectType(rax, FIRST_SPEC_OBJECT_TYPE, rcx);
   __ j(above_equal, &done_convert);
   __ bind(&convert);
   __ push(rax);
   __ InvokeBuiltin(Builtins::TO_OBJECT, CALL_FUNCTION);
   __ bind(&done_convert);
   __ push(rax);
 
+  // Check for proxies.
+  Label call_runtime;
+  STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);
+  __ CmpObjectType(rax, LAST_JS_PROXY_TYPE, rcx);
+  __ j(below_equal, &call_runtime);
+
   // Check cache validity in generated code. This is a fast case for
   // the JSObject::IsSimpleEnum cache validity checks. If we cannot
   // guarantee cache validity, call the runtime system to check cache
   // validity or get the property names in a fixed array.
-  Label next, call_runtime;
+  Label next;
   Register empty_fixed_array_value = r8;
   __ LoadRoot(empty_fixed_array_value, Heap::kEmptyFixedArrayRootIndex);
   Register empty_descriptor_array_value = r9;
   __ LoadRoot(empty_descriptor_array_value,
               Heap::kEmptyDescriptorArrayRootIndex);
   __ movq(rcx, rax);
   __ bind(&next);
 
   // Check that there are no elements.  Register rcx contains the
   // current JS object we've reached through the prototype chain.
@@ skipping 55 matching lines @@
 
   // Setup the four remaining stack slots.
   __ push(rax);  // Map.
   __ push(rdx);  // Enumeration cache.
   __ movq(rax, FieldOperand(rdx, FixedArray::kLengthOffset));
   __ push(rax);  // Enumeration cache length (as smi).
   __ Push(Smi::FromInt(0));  // Initial index.
   __ jmp(&loop);
 
   // We got a fixed array in register rax. Iterate through that.
+  Label non_proxy;
   __ bind(&fixed_array);
-  __ Push(Smi::FromInt(0));  // Map (0) - force slow check.
-  __ push(rax);
+  __ Move(rbx, Smi::FromInt(1));  // Smi indicates slow check
+  __ movq(rcx, Operand(rsp, 0 * kPointerSize));  // Get enumerated object
+  STATIC_ASSERT(FIRST_JS_PROXY_TYPE == FIRST_SPEC_OBJECT_TYPE);
+  __ CmpObjectType(rcx, LAST_JS_PROXY_TYPE, rcx);
+  __ j(above, &non_proxy);
+  __ Move(rbx, Smi::FromInt(0));  // Zero indicates proxy
+  __ bind(&non_proxy);
+  __ push(rbx);  // Smi
+  __ push(rax);  // Array
   __ movq(rax, FieldOperand(rax, FixedArray::kLengthOffset));
   __ push(rax);  // Fixed array length (as smi).
   __ Push(Smi::FromInt(0));  // Initial index.
 
   // Generate code for doing the condition check.
   __ bind(&loop);
   __ movq(rax, Operand(rsp, 0 * kPointerSize));  // Get the current index.
   __ cmpq(rax, Operand(rsp, 1 * kPointerSize));  // Compare to the array length.
   __ j(above_equal, loop_statement.break_label());
 
   // Get the current entry of the array into register rbx.
   __ movq(rbx, Operand(rsp, 2 * kPointerSize));
   SmiIndex index = masm()->SmiToIndex(rax, rax, kPointerSizeLog2);
   __ movq(rbx, FieldOperand(rbx,
                             index.reg,
                             index.scale,
                             FixedArray::kHeaderSize));
 
-  // Get the expected map from the stack or a zero map in the
+  // Get the expected map from the stack or a smi in the
   // permanent slow case into register rdx.
   __ movq(rdx, Operand(rsp, 3 * kPointerSize));
 
   // Check if the expected map still matches that of the enumerable.
-  // If not, we have to filter the key.
+  // If not, we may have to filter the key.
   Label update_each;
   __ movq(rcx, Operand(rsp, 4 * kPointerSize));
   __ cmpq(rdx, FieldOperand(rcx, HeapObject::kMapOffset));
   __ j(equal, &update_each, Label::kNear);
 
+  // For proxies, no filtering is done.
+  // TODO(rossberg): What if only a prototype is a proxy? Not specified yet.
+  __ Cmp(rdx, Smi::FromInt(0));
+  __ j(equal, &update_each, Label::kNear);
+
   // 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(rcx);  // Enumerable.
   __ push(rbx);  // Current entry.
   __ InvokeBuiltin(Builtins::FILTER_KEY, CALL_FUNCTION);
   __ Cmp(rax, Smi::FromInt(0));
   __ j(equal, loop_statement.continue_label());
   __ movq(rbx, rax);
 
@@ skipping 3224 matching lines @@
   *context_length = 0;
   return previous_;
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64