Resolve references to "this" the same way as normal variables

src/arm64/full-codegen-arm64.cc

 // Copyright 2013 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_ARM64
 
 #include "src/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 107 matching lines @@
   if (strlen(FLAG_stop_at) > 0 &&
       info->function()->name()->IsUtf8EqualTo(CStrVector(FLAG_stop_at))) {
     __ Debug("stop-at", __LINE__, BREAK);
   }
 #endif
 
   // Sloppy mode functions and builtins need to replace the receiver with the
   // global proxy when called as functions (without an explicit receiver
   // object).
   if (is_sloppy(info->language_mode()) && !info->is_native() &&
-      info->MayUseThis()) {
+      info->MayUseThis() && info->scope()->has_this_declaration()) {
     Label ok;
     int receiver_offset = info->scope()->num_parameters() * kXRegSize;
     __ Peek(x10, receiver_offset);
     __ JumpIfNotRoot(x10, Heap::kUndefinedValueRootIndex, &ok);
 
     __ Ldr(x10, GlobalObjectMemOperand());
     __ Ldr(x10, FieldMemOperand(x10, GlobalObject::kGlobalProxyOffset));
     __ Poke(x10, receiver_offset);
 
     __ Bind(&ok);
@@ skipping 71 matching lines @@
       __ Push(x1);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
     function_in_register_x1 = false;
     // Context is returned in x0.  It replaces the context passed to us.
     // It's saved in the stack and kept live in cp.
     __ Mov(cp, x0);
     __ Str(x0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = info->scope()->num_parameters();
-    for (int i = 0; i < num_parameters; i++) {
-      Variable* var = scope()->parameter(i);
+    int first_parameter = info->scope()->has_this_declaration() ? -1 : 0;
+    for (int i = first_parameter; i < num_parameters; i++) {
+      Variable* var = (i == -1) ? scope()->receiver() : scope()->parameter(i);
       if (var->IsContextSlot()) {
         int parameter_offset = StandardFrameConstants::kCallerSPOffset +
             (num_parameters - 1 - i) * kPointerSize;
         // Load parameter from stack.
         __ Ldr(x10, MemOperand(fp, parameter_offset));
         // Store it in the context.
         MemOperand target = ContextMemOperand(cp, var->index());
         __ Str(x10, target);
 
         // Update the write barrier.
@@ skipping 2512 matching lines @@
   // Prepare to push a copy of the first argument or undefined if it doesn't
   // exist.
   if (arg_count > 0) {
     __ Peek(x9, arg_count * kXRegSize);
   } else {
     __ LoadRoot(x9, Heap::kUndefinedValueRootIndex);
   }
 
   __ Ldr(x10, MemOperand(fp, JavaScriptFrameConstants::kFunctionOffset));
   // Prepare to push the receiver of the enclosing function.
-  int receiver_offset = 2 + info_->scope()->num_parameters();
-  __ Ldr(x11, MemOperand(fp, receiver_offset * kPointerSize));
+  Variable* this_var = scope()->LookupThis();
+  DCHECK_NOT_NULL(this_var);
+  __ Ldr(x11, VarOperand(this_var, x11));
 
   // Prepare to push the language mode.
   __ Mov(x12, Smi::FromInt(language_mode()));
   // Prepare to push the start position of the scope the calls resides in.
   __ Mov(x13, Smi::FromInt(scope()->start_position()));
 
   // Push.
   __ Push(x9, x10, x11, x12, x13);
 
   // Do the runtime call.
@@ skipping 2714 matching lines @@
     }
   }
 
   return INTERRUPT;
 }
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_ARM64