Implement fast calls of functions in the presence of eval (if the eval...

src/ia32/codegen-ia32.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 4730 matching lines @@
     // containing the eval.
     if (slot->var()->mode() == Variable::DYNAMIC_GLOBAL) {
       result = LoadFromGlobalSlotCheckExtensions(slot, typeof_state, &slow);
       // If there was no control flow to slow, we can exit early.
       if (!slow.is_linked()) return result;
       done.Jump(&result);
 
     } 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.
+      // This rules out argument loads because eval forces arguments
+      // access to be through the arguments object.
       if (potential_slot != NULL) {
         // Allocate a fresh register to use as a temp in
         // ContextSlotOperandCheckExtensions and to hold the result
         // value.
         result = allocator()->Allocate();
         ASSERT(result.is_valid());
         __ mov(result.reg(),
                ContextSlotOperandCheckExtensions(potential_slot,
                                                  result,
                                                  &slow));
@@ skipping 1003 matching lines @@
     CodeForSourcePosition(node->position());
     Result result = frame_->CallCallIC(RelocInfo::CODE_TARGET_CONTEXT,
                                        arg_count,
                                        loop_nesting());
     frame_->RestoreContextRegister();
     frame_->Push(&result);
 
   } else if (var != NULL && var->slot() != NULL &&
              var->slot()->type() == Slot::LOOKUP) {
     // ----------------------------------
-    // JavaScript example: 'with (obj) foo(1, 2, 3)'  // foo is in obj
+    // JavaScript examples:
+    //
+    //  with (obj) foo(1, 2, 3)  // foo is in obj
+    //
+    //  function f() {};
+    //  function g() {
+    //    eval(...);
+    //    f();  // f could be in extension object
+    //  }
     // ----------------------------------
 
-    // Load the function from the context.  Sync the frame so we can
-    // push the arguments directly into place.
+    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.
+      if (potential_slot != NULL) {
+        // Allocate a fresh register to use as a temp in
+        // ContextSlotOperandCheckExtensions and to hold the result
+        // value.
+        function = allocator()->Allocate();
+        ASSERT(function.is_valid());
+        __ mov(function.reg(),
+               ContextSlotOperandCheckExtensions(potential_slot,
+                                                 function,
+                                                 &slow));
+        JumpTarget push_function_and_receiver;
+        if (potential_slot->var()->mode() == Variable::CONST) {
+          __ cmp(function.reg(), Factory::the_hole_value());
+          push_function_and_receiver.Branch(not_equal, &function);
+          __ mov(function.reg(), Factory::undefined_value());
+        }
+        push_function_and_receiver.Bind(&function);
+        frame_->Push(&function);
+        LoadGlobalReceiver();
+        done.Jump();
+      }
+    }
+
+    slow.Bind();
+    // Enter the runtime system to 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(esi);
     frame_->EmitPush(Immediate(var->name()));
     frame_->CallRuntime(Runtime::kLoadContextSlot, 2);
     // The runtime call returns a pair of values in eax and edx.  The
     // looked-up function is in eax and the receiver is in edx.  These
     // register references are not ref counted here.  We spill them
     // eagerly since they are arguments to an inevitable call (and are
     // not sharable by the arguments).
     ASSERT(!allocator()->is_used(eax));
     frame_->EmitPush(eax);
 
     // Load the receiver.
     ASSERT(!allocator()->is_used(edx));
     frame_->EmitPush(edx);
 
+    done.Bind();
     // Call the function.
     CallWithArguments(args, NO_CALL_FUNCTION_FLAGS, node->position());
 
   } else if (property != NULL) {
     // Check if the key is a literal string.
     Literal* literal = property->key()->AsLiteral();
 
     if (literal != NULL && literal->handle()->IsSymbol()) {
       // ------------------------------------------------------------------
       // JavaScript example: 'object.foo(1, 2, 3)' or 'map["key"](1, 2, 3)'
@@ skipping 7337 matching lines @@
 
   // Call the runtime; it returns -1 (less), 0 (equal), or 1 (greater)
   // tagged as a small integer.
   __ bind(&runtime);
   __ TailCallRuntime(Runtime::kStringCompare, 2, 1);
 }
 
 #undef __
 
 } }  // namespace v8::internal