Implement proper scoping for "this" in arrow functions

src/arm/lithium-codegen-arm.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"
 
 #include "src/arm/lithium-codegen-arm.h"
 #include "src/arm/lithium-gap-resolver-arm.h"
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 103 matching lines @@
     // cp: Callee's context.
     // pp: Callee's constant pool pointer (if FLAG_enable_ool_constant_pool)
     // fp: Caller's frame pointer.
     // lr: Caller's pc.
 
     // Sloppy mode functions and builtins need to replace the receiver with the
     // global proxy when called as functions (without an explicit receiver
     // object).
     if (info_->this_has_uses() &&
         info_->strict_mode() == SLOPPY &&
-        !info_->is_native()) {
+        !info_->is_native() &&
+        info_->scope()->has_this_declaration()) {
       Label ok;
       int receiver_offset = info_->scope()->num_parameters() * kPointerSize;
       __ ldr(r2, MemOperand(sp, receiver_offset));
       __ CompareRoot(r2, Heap::kUndefinedValueRootIndex);
       __ b(ne, &ok);
 
       __ ldr(r2, GlobalObjectOperand());
       __ ldr(r2, FieldMemOperand(r2, GlobalObject::kGlobalProxyOffset));
 
       __ str(r2, MemOperand(sp, receiver_offset));
@@ skipping 54 matching lines @@
       __ push(r1);
       __ CallRuntime(Runtime::kNewFunctionContext, 1);
     }
     RecordSafepoint(Safepoint::kNoLazyDeopt);
     // Context is returned in both r0 and cp.  It replaces the context
     // passed to us.  It's saved in the stack and kept live in cp.
     __ mov(cp, r0);
     __ str(r0, MemOperand(fp, StandardFrameConstants::kContextOffset));
     // Copy any necessary parameters into the context.
     int num_parameters = scope()->num_parameters();
-    for (int i = 0; i < num_parameters; i++) {
-      Variable* var = scope()->parameter(i);
+    int first_parameter = 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(r0, MemOperand(fp, parameter_offset));
         // Store it in the context.
         MemOperand target = ContextOperand(cp, var->index());
         __ str(r0, target);
         // Update the write barrier. This clobbers r3 and r0.
         if (need_write_barrier) {
@@ skipping 5745 matching lines @@
   __ Push(scope_info);
   __ push(ToRegister(instr->function()));
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal