Implement fast load and call of arguments in the presence of eval....

src/x64/codegen-x64.cc

 // Copyright 2010 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 2849 matching lines @@
                                        loop_nesting());
     frame_->RestoreContextRegister();
     // Replace the function on the stack with the result.
     frame_->Push(&result);
 
   } else if (var != NULL && var->slot() != NULL &&
              var->slot()->type() == Slot::LOOKUP) {
     // ----------------------------------
     // JavaScript examples:
     //
-    //  with (obj) foo(1, 2, 3)  // foo is in obj
+    //  with (obj) foo(1, 2, 3)  // foo may be in obj.
     //
     //  function f() {};
     //  function g() {
     //    eval(...);
-    //    f();  // f could be in extension object
+    //    f();  // f could be in extension object.
     //  }
     // ----------------------------------
 
     JumpTarget slow;
     JumpTarget done;
 
     // Generate fast-case code for variables that might be shadowed by
     // eval-introduced variables.  Eval is used a lot without
     // introducing variables.  In those cases, we do not want to
     // perform a runtime call for all variables in the scope
     // containing the eval.
     Result function;
     if (var->mode() == Variable::DYNAMIC_GLOBAL) {
       function = LoadFromGlobalSlotCheckExtensions(var->slot(),
                                                    NOT_INSIDE_TYPEOF,
                                                    &slow);
       frame_->Push(&function);
       LoadGlobalReceiver();
       done.Jump();
 
     } else if (var->mode() == Variable::DYNAMIC_LOCAL) {
       Slot* potential_slot = var->local_if_not_shadowed()->slot();
-      // Only generate the fast case for locals that rewrite to slots.
-      // This rules out argument loads because eval forces arguments
-      // access to be through the arguments object.
+      Expression* rewrite = var->local_if_not_shadowed()->rewrite();
       if (potential_slot != NULL) {
+        // Generate fast case for locals that rewrite to slots.
         // Allocate a fresh register to use as a temp in
         // ContextSlotOperandCheckExtensions and to hold the result
         // value.
         function = allocator()->Allocate();
         ASSERT(function.is_valid());
         __ movq(function.reg(),
                 ContextSlotOperandCheckExtensions(potential_slot,
                                                   function,
                                                   &slow));
         JumpTarget push_function_and_receiver;
         if (potential_slot->var()->mode() == Variable::CONST) {
           __ CompareRoot(function.reg(), Heap::kTheHoleValueRootIndex);
           push_function_and_receiver.Branch(not_equal, &function);
           __ LoadRoot(function.reg(), Heap::kUndefinedValueRootIndex);
         }
         push_function_and_receiver.Bind(&function);
         frame_->Push(&function);
         LoadGlobalReceiver();
         done.Jump();
+      } else if (rewrite != NULL) {
+        // Generate fast case for calls of an argument function.
+        Property* property = rewrite->AsProperty();
+        if (property != NULL) {
+          VariableProxy* obj_proxy = property->obj()->AsVariableProxy();
+          Literal* key_literal = property->key()->AsLiteral();
+          if (obj_proxy != NULL &&
+              key_literal != NULL &&
+              obj_proxy->IsArguments() &&
+              key_literal->handle()->IsSmi()) {
+            // Load arguments object if there are no eval-introduced
+            // variables. Then load the argument from the arguments
+            // object using keyed load.
+            Result arguments = allocator()->Allocate();
+            ASSERT(arguments.is_valid());
+            __ movq(arguments.reg(),
+                    ContextSlotOperandCheckExtensions(obj_proxy->var()->slot(),
+                                                      arguments,
+                                                      &slow));
+            frame_->Push(&arguments);
+            frame_->Push(key_literal->handle());
+            Result value = EmitKeyedLoad(false);
+            frame_->Drop(2);  // Drop key and receiver.
+            frame_->Push(&value);
+            LoadGlobalReceiver();
+            done.Jump();
+          }
+        }
       }
     }
 
     slow.Bind();
     // Load the function from the context.  Sync the frame so we can
     // push the arguments directly into place.
     frame_->SyncRange(0, frame_->element_count() - 1);
     frame_->EmitPush(rsi);
     frame_->EmitPush(var->name());
     frame_->CallRuntime(Runtime::kLoadContextSlot, 2);
@@ skipping 2404 matching lines @@
     JumpTarget done;
     Result value;
 
     // Generate fast-case code for variables that might be shadowed by
     // eval-introduced variables.  Eval is used a lot without
     // introducing variables.  In those cases, we do not want to
     // perform a runtime call for all variables in the scope
     // containing the eval.
     if (slot->var()->mode() == Variable::DYNAMIC_GLOBAL) {
       value = LoadFromGlobalSlotCheckExtensions(slot, typeof_state, &slow);
-      // If there was no control flow to slow, we can exit early.
-      if (!slow.is_linked()) {
-        frame_->Push(&value);
-        return;
-      }
-
       done.Jump(&value);
 
     } else if (slot->var()->mode() == Variable::DYNAMIC_LOCAL) {
       Slot* potential_slot = slot->var()->local_if_not_shadowed()->slot();
-      // Only generate the fast case for locals that rewrite to slots.
-      // This rules out argument loads because eval forces arguments
-      // access to be through the arguments object.
+      Expression* rewrite = slot->var()->local_if_not_shadowed()->rewrite();
       if (potential_slot != NULL) {
+        // Generate fast case for locals that rewrite to slots.
         // Allocate a fresh register to use as a temp in
         // ContextSlotOperandCheckExtensions and to hold the result
         // value.
         value = allocator_->Allocate();
         ASSERT(value.is_valid());
         __ movq(value.reg(),
                ContextSlotOperandCheckExtensions(potential_slot,
                                                  value,
                                                  &slow));
         if (potential_slot->var()->mode() == Variable::CONST) {
           __ CompareRoot(value.reg(), Heap::kTheHoleValueRootIndex);
           done.Branch(not_equal, &value);
           __ LoadRoot(value.reg(), Heap::kUndefinedValueRootIndex);
         }
-        // There is always control flow to slow from
-        // ContextSlotOperandCheckExtensions so we have to jump around
-        // it.
         done.Jump(&value);
+      } else if (rewrite != NULL) {
+        // Generate fast case for argument loads.
+        Property* property = rewrite->AsProperty();
+        if (property != NULL) {
+          VariableProxy* obj_proxy = property->obj()->AsVariableProxy();
+          Literal* key_literal = property->key()->AsLiteral();
+          if (obj_proxy != NULL &&
+              key_literal != NULL &&
+              obj_proxy->IsArguments() &&
+              key_literal->handle()->IsSmi()) {
+            // Load arguments object if there are no eval-introduced
+            // variables. Then load the argument from the arguments
+            // object using keyed load.
+            Result arguments = allocator()->Allocate();
+            ASSERT(arguments.is_valid());
+            __ movq(arguments.reg(),
+                    ContextSlotOperandCheckExtensions(obj_proxy->var()->slot(),
+                                                      arguments,
+                                                      &slow));
+            frame_->Push(&arguments);
+            frame_->Push(key_literal->handle());
+            value = EmitKeyedLoad(false);
+            frame_->Drop(2);  // Drop key and receiver.
+            done.Jump(&value);
+          }
+        }
       }
     }
 
     slow.Bind();
     // A runtime call is inevitable.  We eagerly sync frame elements
     // to memory so that we can push the arguments directly into place
     // on top of the frame.
     frame_->SyncRange(0, frame_->element_count() - 1);
     frame_->EmitPush(rsi);
     __ movq(kScratchRegister, slot->var()->name(), RelocInfo::EMBEDDED_OBJECT);
@@ skipping 6142 matching lines @@
   // Call the function from C++.
   return FUNCTION_CAST<ModuloFunction>(buffer);
 }
 
 #endif
 
 
 #undef __
 
 } }  // namespace v8::internal