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

src/arm/codegen-arm.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 2758 matching lines @@
     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.
     if (slot->var()->mode() == Variable::DYNAMIC_GLOBAL) {
       LoadFromGlobalSlotCheckExtensions(slot, typeof_state, &slow);
-      // If there was no control flow to slow, we can exit early.
-      if (!slow.is_linked()) {
-        frame_->EmitPush(r0);
-        return;
-      }
       frame_->SpillAll();
-
       done.Jump();
 
     } else if (slot->var()->mode() == Variable::DYNAMIC_LOCAL) {
       frame_->SpillAll();
       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.
         __ ldr(r0,
                ContextSlotOperandCheckExtensions(potential_slot,
                                                  r1,
                                                  r2,
                                                  &slow));
         if (potential_slot->var()->mode() == Variable::CONST) {
           __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
           __ cmp(r0, ip);
           __ LoadRoot(r0, Heap::kUndefinedValueRootIndex, eq);
         }
-        // There is always control flow to slow from
-        // ContextSlotOperandCheckExtensions so we have to jump around
-        // it.
         done.Jump();
+      } 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.
+            __ ldr(r0,
+                   ContextSlotOperandCheckExtensions(obj_proxy->var()->slot(),
+                                                     r1,
+                                                     r2,
+                                                     &slow));
+            frame_->EmitPush(r0);
+            __ mov(r1, Operand(key_literal->handle()));
+            frame_->EmitPush(r1);
+            EmitKeyedLoad();
+            done.Jump();
+          }
+        }
       }
     }
 
     slow.Bind();
     VirtualFrame::SpilledScope spilled_scope(frame_);
     frame_->EmitPush(cp);
     __ mov(r0, Operand(slot->var()->name()));
     frame_->EmitPush(r0);
 
     if (typeof_state == INSIDE_TYPEOF) {
@@ skipping 882 matching lines @@
     frame_->CallCodeObject(stub, RelocInfo::CODE_TARGET_CONTEXT,
                            arg_count + 1);
     __ ldr(cp, frame_->Context());
     frame_->EmitPush(r0);
 
   } 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.
     //  }
     // ----------------------------------
 
     // JumpTargets do not yet support merging frames so the frame must be
     // spilled when jumping to these targets.
     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.
     if (var->mode() == Variable::DYNAMIC_GLOBAL) {
       LoadFromGlobalSlotCheckExtensions(var->slot(), NOT_INSIDE_TYPEOF, &slow);
       frame_->EmitPush(r0);
       LoadGlobalReceiver(r1);
       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.
         __ ldr(r0,
                ContextSlotOperandCheckExtensions(potential_slot,
                                                  r1,
                                                  r2,
                                                  &slow));
         if (potential_slot->var()->mode() == Variable::CONST) {
           __ LoadRoot(ip, Heap::kTheHoleValueRootIndex);
           __ cmp(r0, ip);
           __ LoadRoot(r0, Heap::kUndefinedValueRootIndex, eq);
         }
         frame_->EmitPush(r0);
         LoadGlobalReceiver(r1);
         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.
+            __ ldr(r0,
+                   ContextSlotOperandCheckExtensions(obj_proxy->var()->slot(),
+                                                     r1,
+                                                     r2,
+                                                     &slow));
+            frame_->EmitPush(r0);
+            __ mov(r1, Operand(key_literal->handle()));
+            frame_->EmitPush(r1);
+            EmitKeyedLoad();
+            frame_->EmitPush(r0);
+            LoadGlobalReceiver(r1);
+            done.Jump();
+          }
+        }
       }
     }
 
     slow.Bind();
     // Load the function
     frame_->EmitPush(cp);
     __ mov(r0, Operand(var->name()));
     frame_->EmitPush(r0);
     frame_->CallRuntime(Runtime::kLoadContextSlot, 2);
     // r0: slot value; r1: receiver
@@ skipping 6195 matching lines @@
 
   // Just jump to runtime to add the two strings.
   __ bind(&string_add_runtime);
   __ TailCallRuntime(Runtime::kStringAdd, 2, 1);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal