Revert change 3849. On ia32, LoadFromSlot again returns its result on the top...

Revert change 3849.  On ia32, LoadFromSlot again returns its result on the top of the expression stack, not as a Result return value.
Review URL: http://codereview.chromium.org/2121014

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4700 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/ia32/codegen-ia32.cc

@@ -695,9 +695,7 @@ void CodeGenerator::LoadTypeofExpression(Expression* expr) {
   } else if (variable != NULL && variable->slot() != NULL) {
     // For a variable that rewrites to a slot, we signal it is the immediate
     // subexpression of a typeof.
-    Result result =
-        LoadFromSlotCheckForArguments(variable->slot(), INSIDE_TYPEOF);
-    frame()->Push(&result);
+    LoadFromSlotCheckForArguments(variable->slot(), INSIDE_TYPEOF);
   } else {
     // Anything else can be handled normally.
     Load(expr);
@@ -746,7 +744,8 @@ Result CodeGenerator::StoreArgumentsObject(bool initial) {
     // We have to skip storing into the arguments slot if it has already
     // been written to. This can happen if the a function has a local
     // variable named 'arguments'.
-    Result probe = LoadFromSlot(arguments->slot(), NOT_INSIDE_TYPEOF);
+    LoadFromSlot(arguments->slot(), NOT_INSIDE_TYPEOF);
+    Result probe = frame_->Pop();
     if (probe.is_constant()) {
       // We have to skip updating the arguments object if it has
       // been assigned a proper value.
@@ -3026,9 +3025,7 @@ void CodeGenerator::CallApplyLazy(Expression* applicand,
   // Load the receiver and the existing arguments object onto the
   // expression stack. Avoid allocating the arguments object here.
   Load(receiver);
-  Result existing_args =
-      LoadFromSlot(scope()->arguments()->var()->slot(), NOT_INSIDE_TYPEOF);
-  frame()->Push(&existing_args);
+  LoadFromSlot(scope()->arguments()->var()->slot(), NOT_INSIDE_TYPEOF);
 
   // Emit the source position information after having loaded the
   // receiver and the arguments.
@@ -4719,19 +4716,19 @@ void CodeGenerator::VisitConditional(Conditional* node) {
 }
 
 
-Result CodeGenerator::LoadFromSlot(Slot* slot, TypeofState typeof_state) {
-  Result result;
+void CodeGenerator::LoadFromSlot(Slot* slot, TypeofState typeof_state) {
   if (slot->type() == Slot::LOOKUP) {
     ASSERT(slot->var()->is_dynamic());
     JumpTarget slow;
     JumpTarget done;
+    Result value;
 
     // Generate fast case for loading from slots that correspond to
     // local/global variables or arguments unless they are shadowed by
     // eval-introduced bindings.
     EmitDynamicLoadFromSlotFastCase(slot,
                                     typeof_state,
-                                    &result,
+                                    &value,
                                     &slow,
                                     &done);
 
@@ -4743,14 +4740,14 @@ Result CodeGenerator::LoadFromSlot(Slot* slot, TypeofState typeof_state) {
     frame()->EmitPush(esi);
     frame()->EmitPush(Immediate(slot->var()->name()));
     if (typeof_state == INSIDE_TYPEOF) {
-      result =
+      value =
           frame()->CallRuntime(Runtime::kLoadContextSlotNoReferenceError, 2);
     } else {
-      result = frame()->CallRuntime(Runtime::kLoadContextSlot, 2);
+      value = frame()->CallRuntime(Runtime::kLoadContextSlot, 2);
     }
 
-    done.Bind(&result);
-    return result;
+    done.Bind(&value);
+    frame_->Push(&value);
 
   } else if (slot->var()->mode() == Variable::CONST) {
     // Const slots may contain 'the hole' value (the constant hasn't been
@@ -4767,15 +4764,13 @@ Result CodeGenerator::LoadFromSlot(Slot* slot, TypeofState typeof_state) {
     __ j(not_equal, &exit);
     __ mov(ecx, Factory::undefined_value());
     __ bind(&exit);
-    return Result(ecx);
+    frame()->EmitPush(ecx);
 
   } else if (slot->type() == Slot::PARAMETER) {
     frame()->PushParameterAt(slot->index());
-    return frame()->Pop();
 
   } else if (slot->type() == Slot::LOCAL) {
     frame()->PushLocalAt(slot->index());
-    return frame()->Pop();
 
   } else {
     // The other remaining slot types (LOOKUP and GLOBAL) cannot reach
@@ -4784,46 +4779,48 @@ Result CodeGenerator::LoadFromSlot(Slot* slot, TypeofState typeof_state) {
     // The use of SlotOperand below is safe for an unspilled frame
     // because it will always be a context slot.
     ASSERT(slot->type() == Slot::CONTEXT);
-    result = allocator()->Allocate();
-    ASSERT(result.is_valid());
-    __ mov(result.reg(), SlotOperand(slot, result.reg()));
-    return result;
+    Result temp = allocator()->Allocate();
+    ASSERT(temp.is_valid());
+    __ mov(temp.reg(), SlotOperand(slot, temp.reg()));
+    frame()->Push(&temp);
   }
 }
 
 
-Result CodeGenerator::LoadFromSlotCheckForArguments(Slot* slot,
+void CodeGenerator::LoadFromSlotCheckForArguments(Slot* slot,
                                                     TypeofState state) {
-  Result result = LoadFromSlot(slot, state);
+  LoadFromSlot(slot, state);
 
   // Bail out quickly if we're not using lazy arguments allocation.
-  if (ArgumentsMode() != LAZY_ARGUMENTS_ALLOCATION) return result;
+  if (ArgumentsMode() != LAZY_ARGUMENTS_ALLOCATION) return;
 
   // ... or if the slot isn't a non-parameter arguments slot.
-  if (slot->type() == Slot::PARAMETER || !slot->is_arguments()) return result;
+  if (slot->type() == Slot::PARAMETER || !slot->is_arguments()) return;
 
   // If the loaded value is a constant, we know if the arguments
   // object has been lazily loaded yet.
+  Result result = frame()->Pop();
   if (result.is_constant()) {
     if (result.handle()->IsTheHole()) {
-      result.Unuse();
-      return StoreArgumentsObject(false);
-    } else {
-      return result;
+      result = StoreArgumentsObject(false);
     }
+    frame()->Push(&result);
+    return;
   }
-
+  ASSERT(result.is_register());
   // The loaded value is in a register. If it is the sentinel that
   // indicates that we haven't loaded the arguments object yet, we
   // need to do it now.
   JumpTarget exit;
   __ cmp(Operand(result.reg()), Immediate(Factory::the_hole_value()));
-  exit.Branch(not_equal, &result);
+  frame()->Push(&result);
+  exit.Branch(not_equal);
 
-  result.Unuse();
   result = StoreArgumentsObject(false);
-  exit.Bind(&result);
-  return result;
+  frame()->SetElementAt(0, &result);
+  result.Unuse();
+  exit.Bind();
+  return;
 }
 
 
@@ -5073,8 +5070,7 @@ void CodeGenerator::VisitSlot(Slot* slot) {
       UNREACHABLE();
     }
   } else {
-    Result result = LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
-    frame()->Push(&result);
+    LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
   }
 }
 
@@ -5395,8 +5391,7 @@ void CodeGenerator::EmitSlotAssignment(Assignment* node) {
   if (node->is_compound()) {
     // For a compound assignment the right-hand side is a binary operation
     // between the current property value and the actual right-hand side.
-    Result result = LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
-    frame()->Push(&result);
+    LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
     Load(node->value());
 
     // Perform the binary operation.
@@ -8857,10 +8852,8 @@ void Reference::GetValue() {
       Comment cmnt(masm, "[ Load from Slot");
       Slot* slot = expression_->AsVariableProxy()->AsVariable()->slot();
       ASSERT(slot != NULL);
-      Result result =
-          cgen_->LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
+      cgen_->LoadFromSlotCheckForArguments(slot, NOT_INSIDE_TYPEOF);
       if (!persist_after_get_) set_unloaded();
-      cgen_->frame()->Push(&result);
       break;
     }
 

src/ia32/codegen-ia32.h

@@ -459,8 +459,8 @@ class CodeGenerator: public AstVisitor {
   void LoadWithSafeInt32ModeDisabled(Expression* expr);
 
   // Read a value from a slot and leave it on top of the expression stack.
-  Result LoadFromSlot(Slot* slot, TypeofState typeof_state);
-  Result LoadFromSlotCheckForArguments(Slot* slot, TypeofState typeof_state);
+  void LoadFromSlot(Slot* slot, TypeofState typeof_state);
+  void LoadFromSlotCheckForArguments(Slot* slot, TypeofState typeof_state);
   Result LoadFromGlobalSlotCheckExtensions(Slot* slot,
                                            TypeofState typeof_state,
                                            JumpTarget* slow);