[proxy] fixing harmony/proxy.js tests and improving error messages + some drive-by fixes

src/full-codegen/mips64/full-codegen-mips64.cc

Index: src/full-codegen/mips64/full-codegen-mips64.cc
diff --git a/src/full-codegen/mips64/full-codegen-mips64.cc b/src/full-codegen/mips64/full-codegen-mips64.cc
index 4979132ec6610816e802ec135bb0c9c04f2512a6..b426e301482bfa2e88fc38fa9ba22e4af787ecfd 100644
--- a/src/full-codegen/mips64/full-codegen-mips64.cc
+++ b/src/full-codegen/mips64/full-codegen-mips64.cc
@@ -1091,7 +1091,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ jmp(&exit);
 
   // We got a fixed array in register v0. Iterate through that.
-  Label non_proxy;
   __ bind(&fixed_array);
 
   __ EmitLoadTypeFeedbackVector(a1);
@@ -1099,13 +1098,7 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   int vector_index = SmiFromSlot(slot)->value();
   __ sd(a2, FieldMemOperand(a1, FixedArray::OffsetOfElementAt(vector_index)));
 
-  __ li(a1, Operand(Smi::FromInt(1)));  // Smi indicates slow check
-  __ ld(a2, MemOperand(sp, 0 * kPointerSize));  // Get enumerated object
-  STATIC_ASSERT(JS_PROXY_TYPE == FIRST_JS_RECEIVER_TYPE);
-  __ GetObjectType(a2, a3, a3);
-  __ Branch(&non_proxy, gt, a3, Operand(JS_PROXY_TYPE));
-  __ li(a1, Operand(Smi::FromInt(0)));  // Zero indicates proxy
-  __ bind(&non_proxy);
+  __ li(a1, Operand(Smi::FromInt(1)));  // Smi(1) indicates slow check
   __ Push(a1, v0);  // Smi and array
   __ ld(a1, FieldMemOperand(v0, FixedArray::kLengthOffset));
   __ li(a0, Operand(Smi::FromInt(0)));
@@ -1138,11 +1131,6 @@ void FullCodeGenerator::VisitForInStatement(ForInStatement* stmt) {
   __ ld(a4, FieldMemOperand(a1, HeapObject::kMapOffset));
   __ Branch(&update_each, eq, a4, Operand(a2));
 
-  // For proxies, no filtering is done.
-  // TODO(rossberg): What if only a prototype is a proxy? Not specified yet.
-  DCHECK_EQ(static_cast<Smi*>(0), Smi::FromInt(0));
-  __ Branch(&update_each, eq, a2, Operand(zero_reg));
-
   // 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.