Add script context with context-allocated "const this"

src/x87/full-codegen-x87.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/v8.h"
 
 #if V8_TARGET_ARCH_X87
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 2975 matching lines @@
 void FullCodeGenerator::EmitResolvePossiblyDirectEval(int arg_count) {
   // Push copy of the first argument or undefined if it doesn't exist.
   if (arg_count > 0) {
     __ push(Operand(esp, arg_count * kPointerSize));
   } else {
     __ push(Immediate(isolate()->factory()->undefined_value()));
   }
 
   // Push the enclosing function.
   __ push(Operand(ebp, JavaScriptFrameConstants::kFunctionOffset));
-  // Push the receiver of the enclosing function.
-  Variable* this_var = scope()->LookupThis();
-  DCHECK_NOT_NULL(this_var);
-  __ push(VarOperand(this_var, ecx));
+
   // Push the language mode.
   __ push(Immediate(Smi::FromInt(language_mode())));
 
   // Push the start position of the scope the calls resides in.
   __ push(Immediate(Smi::FromInt(scope()->start_position())));
 
   // Do the runtime call.
-  __ CallRuntime(Runtime::kResolvePossiblyDirectEval, 6);
+  __ CallRuntime(Runtime::kResolvePossiblyDirectEval, 5);
 }
 
 
 void FullCodeGenerator::EmitInitializeThisAfterSuper(
     SuperCallReference* super_call_ref, FeedbackVectorICSlot slot) {
   Variable* this_var = super_call_ref->this_var()->var();
   GetVar(ecx, this_var);
   __ cmp(ecx, isolate()->factory()->the_hole_value());
   Label uninitialized_this;
   __ j(equal, &uninitialized_this);
@@ skipping 11 matching lines @@
   // through this function.  Avoid early returns.
   expr->return_is_recorded_ = false;
 #endif
 
   Comment cmnt(masm_, "[ Call");
   Expression* callee = expr->expression();
   Call::CallType call_type = expr->GetCallType(isolate());
 
   if (call_type == Call::POSSIBLY_EVAL_CALL) {
     // In a call to eval, we first call RuntimeHidden_ResolvePossiblyDirectEval
-    // to resolve the function we need to call and the receiver of the call.
-    // Then we call the resolved function using the given arguments.
+    // to resolve the function we need to call.  Then we call the resolved
+    // function using the given arguments.
     ZoneList<Expression*>* args = expr->arguments();
     int arg_count = args->length();
     { PreservePositionScope pos_scope(masm()->positions_recorder());
       VisitForStackValue(callee);
       // Reserved receiver slot.
       __ push(Immediate(isolate()->factory()->undefined_value()));
       // Push the arguments.
       for (int i = 0; i < arg_count; i++) {
         VisitForStackValue(args->at(i));
       }
 
       // Push a copy of the function (found below the arguments) and
       // resolve eval.
       __ push(Operand(esp, (arg_count + 1) * kPointerSize));
       EmitResolvePossiblyDirectEval(arg_count);
 
-      // The runtime call returns a pair of values in eax (function) and
-      // edx (receiver). Touch up the stack with the right values.
-      __ mov(Operand(esp, (arg_count + 0) * kPointerSize), edx);
+      // Touch up the stack with the resolved function.
       __ mov(Operand(esp, (arg_count + 1) * kPointerSize), eax);
 
       PrepareForBailoutForId(expr->EvalOrLookupId(), NO_REGISTERS);
     }
     // Record source position for debugger.
     SetSourcePosition(expr->position());
     CallFunctionStub stub(isolate(), arg_count, NO_CALL_FUNCTION_FLAGS);
     __ mov(edi, Operand(esp, (arg_count + 1) * kPointerSize));
     __ CallStub(&stub);
     RecordJSReturnSite(expr);
@@ skipping 1598 matching lines @@
       VariableProxy* proxy = expr->expression()->AsVariableProxy();
 
       if (property != NULL) {
         VisitForStackValue(property->obj());
         VisitForStackValue(property->key());
         __ push(Immediate(Smi::FromInt(language_mode())));
         __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
         context()->Plug(eax);
       } else if (proxy != NULL) {
         Variable* var = proxy->var();
-        // Delete of an unqualified identifier is disallowed in strict mode
-        // but "delete this" is allowed.
-        DCHECK(is_sloppy(language_mode()) || var->is_this());
+        // Delete of an unqualified identifier is disallowed in strict mode but
+        // "delete this" is allowed.  (It could be that the "this" variable has
+        // DYNAMIC resolution though so we haven't been able to map it to
+        // Variable::THIS, but regardless if its name is "this" then it is
+        // "this".)
+        bool is_this = *var->name() == *isolate()->factory()->this_string();
+        DCHECK(is_sloppy(language_mode()) || is_this);
         if (var->IsUnallocated()) {
           __ push(GlobalObjectOperand());
           __ push(Immediate(var->name()));
           __ push(Immediate(Smi::FromInt(SLOPPY)));
           __ InvokeBuiltin(Builtins::DELETE, CALL_FUNCTION);
           context()->Plug(eax);
         } else if (var->IsStackAllocated() || var->IsContextSlot()) {
           // Result of deleting non-global variables is false.  'this' is
           // not really a variable, though we implement it as one.  The
           // subexpression does not have side effects.
-          context()->Plug(var->is_this());
+          context()->Plug(is_this);
         } else {
           // Non-global variable.  Call the runtime to try to delete from the
           // context where the variable was introduced.
           __ push(context_register());
           __ push(Immediate(var->name()));
           __ CallRuntime(Runtime::kDeleteLookupSlot, 2);
           context()->Plug(eax);
         }
       } else {
         // Result of deleting non-property, non-variable reference is true.
@@ skipping 735 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X87